Guide number - Knowledge

5548:, made by Conley Camera Company, from Sears Roebuck for $ 4.75–$ 21.50 (equivalent to $ 170–$ 764 in 2024). With the exception of entry-level models, both view-type and folding cameras of this era came with a detachable pneumatic shutter release with a rubber bulb on the end, as seen at right on the $ 11.75 Model C. With the exception of their entry-level shutter, Conley's shutters—like the Conley Automatic (inset, far right)—had a "B" setting. Though mechanically timed exposures too could be triggered by squeezing the shutter release bulb, "bulb" exposures had the same momentary action as camera shutters have today, as per this description from Sears Roebuck's 1909 1358:

models, virtually all modern on-camera flash devices feature either a built-in mechanical circular calculator (such as shown in the photo at the top of this article) or—more modern yet—a digital display; both methods automatically calculate the effect ISO settings have on f‑stop and distance (guide number). Such features make it exceedingly easy to find a suitable combination of f‑stop and distance so photographers seldom need to concern themselves with the mathematical details underlying how their flash devices' guide number changes with different ISO sensitivities.

5519: 1324: 2249: 440: 20: 143:

practice demands industry-wide standardization of both the ISO setting and illumination angle underlying the ratings; this has only been partially realized. For the most part, manufacturers state guide numbers relative to a sensitivity of ISO 100. However, manufacturers sometimes rate guide numbers at ISO 200, which makes them 41% greater. Furthermore, the illumination angles underlying manufacturers' ratings vary greatly, which can make it particularly difficult to compare models.

2261: 7784: 157: 2241: 7795: 3439: 3788:. For end users, obtaining proper exposures with flashbulbs was an error-prone effort as they mentally interpolated between distances and f‑stop combinations that weren't very accurate in the first place. Had the guide number system existed by this point, the above table would not have required the left-most column showing distances and would have required only one row (showing guide numbers) under each heading. 645:, below. When comparing or shopping for flash devices, it is important to ensure that the guide numbers are given in the same ISO sensitivity, are for the same coverage angle, and reduce to the same unit of distance (meters or feet). When these three variables have been normalized, guide numbers can serve as an relative measure of intrinsic illuminating energy rather than an inconstant metric for calculating exposures. 3466:. In 1929, Sashalite Limited in London invented the "Sashalite" flashbulb, which was filled with a crumpled wad of aluminum foil so thin (about one-tenth the width of a human hair) it could not be picked up with fingers. The Sashalite, which was manufactured under contract by General Electric Co., Ltd. in London, came with an instruction sheet directing photographers to insert the Sashalite into "an ordinary electric 128:) and flash coverage angle. For any given ISO setting and coverage angle however, an inherently more powerful flash device featuring a guide number that is, for instance, twice as great will permit subjects to be properly exposed from twice as far away for any given f‑stop, or conversely, will permit scenes at a given distance to be properly exposed at an f‑number twice as great. 3854:(1941) used the term "guide number" on page 47, on the very next page used the term "Flash Number" (title case), and later still used the term "flash number" (lowercase). Terminology was similarly mixed in the United Kingdom for years after the introduction of the guide number system; circa 1954, "Flash Factor", "Flash number" (and sometimes "Guide number") were in use. 615:

using a camera with a through-the-lens meter to photograph a park bench surrounded by sunlit snow underexposes the image, making the bench appear nearly black and the snow as dark as grass and foliage. This is because reflected-light meters are calibrated for an average scene reflectance of 18 percent and can't "know" when a scene has non-average reflectance. See also

1128:, and add-on wide-angle adapter). Accordingly, there is no universal formula for precisely calculating how guide numbers diminish from, for instance, a 105 mm setting to 50 mm or 35 mm settings. One may consult the users guide for a specific flash device to obtain guide numbers for different zoom settings. 139:, which make it trivially easy, quick, and inexpensive to adjust exposures and try again. Still, guide numbers in combination with flash devices set to manual exposure mode remain valuable in a variety of circumstances, such as when unusual or exacting results are required and when shooting non-average scenery. 2612:

were characterized by rapid rise and fall rates; the second shutter curtain would begin wiping shut during a period of rapid change in scene illuminance, causing uneven exposure across the image area that varied in nature depending on exposure duration and the type of bulb. With the GE Synchro‑Press

2669:

The tables below show the distances at which deep shadows will be filled with one f‑stop less than the sunlit portions of the scene, which is a common fill level. The exposures given here assume average frontlit subjects under bright or hazy sun with distinct shadows for photos taken between 2

1385:

that seldom if ever permit extremely long-range flash photography due to particulates and aerosols typically present in outside air that fog images with haze glare and attenuate the reach of the light. Except in unusual atmospheric conditions, extraordinarily large guide numbers will produce suitable

1357:

To allow photographers to properly calculate exposures, even older, base-model flash devices have at least a tabular table on the device showing its guide number for a limited range of common ISO sensitivities. Today, the state of the art has advanced so that with the exception of the least expensive

142:

Different models of flash devices available on the market have widely varying maximum-rated guide numbers. Since guide numbers are so familiar to photographers, they are near-universally used by manufacturers of on-camera flash devices to advertise their products' relative capability. However, such a

5282:

formula when using the f‑stops shown in the first column because the fill-flash contribution is one f‑stop less than the sunlit portions of the scene—a 50% underexposure. The values may be correctly calculated by hand when the apertures shown in the first column are larger (numerically

3521:

by the Journal of the Photographic Society of America featured an exposure table for foil-filled flashbulbs, which is shown below. The parenthetical values in bold were not part of the original table; they show the equivalent guide number for each aperture-distance combination. Note the scatter in

3505:

introduced what was arguably the first modern flashbulb with wire fill under the trade name "Hydronalium". Philips' technology was licensed in 1937 by Wabash Photolamp Corporation and introduced to the U.S. market as Superflash bulbs. Shortly later, in 1939, General Electric under their MAZDA brand

2650:

outdoors, powerful flash devices (those with inherently greater guide numbers when compared at the same ISO sensitivity and coverage angle) can be useful because they permit photographers to increase the maximum flash-to-subject distance, such as when taking group photos. Clearly, more power helps

2611:

Cameras with focal-plane shutters—even if they had PC connectors with X, F, M, or S-sync delays ("xenon sync" with zero delay and flashbulbs with peak delays of 5, 20, and 30 ms)—could not be used at speeds that attenuated guide numbers with most types of flashbulbs because their light curves

2315:

This is because even at the most powerful settings, flash durations seldom exceed a few milliseconds (thousandths of a second). With focal-plane shutters, a flash begins shortly after the shutter curtain has fully opened and must extinguish before the curtain begins to close. Selecting any shutter

1353:

Among other variables like illumination angle (for devices with zoomable flash heads) and power setting, guide numbers are a function of the ISO sensitivity (film speed or ISO setting on a digital camera). Guide numbers change as the square root of the difference in ISO sensitivity. Accordingly, a

1111:

Nonetheless, when comparing or shopping for flash devices with zoom heads, it would certainly be helpful if it were possible to mathematically convert advertised guide numbers from one manufacturer's flash angle (zoom level) to another manufacturer's flash angle. This is because guide numbers are

5566:

sold cameras before the flashbulb era too. Though their entry level consumer cameras came without the option of a pneumatic shutter release, Kodak retained the convention of using "B” on shutters for the momentary actuation setting but referred to it as "Brief Time" in brochures for cameras like

2076:

When a flash device is set to manual (M) or automatic (A) exposure mode and is not being controlled via the camera's through-the-lens metering, a convenient way to compensate for the effect of a lens-mounted filter is to set the ISO rating on a camera to a higher value than the flash device. For

1107:

Virtually all modern on-camera flash devices with zoomable flash heads also have either a built-in mechanical circular calculator (such as shown in the photo at the top of this article) or a digital display; both automatically show the effect zoom levels have on f‑stop and distance (guide

1099:

Many flash devices have auto- or manual-adjust zoom features that permit the illumination angle to be widened (lessening the guide number) to fully illuminate the image area of wide-angle lenses, or narrowed (increasing the guide number) for telephoto lenses. Such coverage angles may be given in

614:

at a scene as measured by an incident-light meter (pictured at right), not the amount leaving the scene. This often seems counterintuitive to hobbyists who incorrectly assume that cameras' built-in reflected-light meters are a definitive measure of exposure. However, this principle underlies why

546:

Most modern flash devices can operate at guide numbers less than their maximum ratings via either manual adjustment of their power settings in binned steps, by an in-flash automatic light sensing feature, or by being cued by the camera's sensor; both the latter options make continuously variable

2336:

of a second (from as long as 16.7 milliseconds to as little as 5.0 milliseconds) causes the shutter curtain to begin wiping closed across the film or sensor before the flash has extinguished. When this happens, an underexposed, gradated band appears along an edge of the image—often trailing off

1361:

Still, it can be helpful when comparing flash devices to understand how guide numbers vary with ISO sensitivity. Usually manufacturers state their products' guide number ratings relative to an ISO sensitivity of 100. However, some manufacturers of flash devices may provide guide numbers ratings

4154:

The dual-scale format used for many examples of guide numbers within this article (similar to the practice observed by Metz mecatech GmbH and others) is purely a matter of style. It is used here not only because it is relatively compact, but because by observing the convention of enclosing the

3803:

featured a guide number table. Perhaps so as to not intimidate readers, that table still showed numerous combinations of distances and apertures, but it also featured a new column showing the guide number that every cell in its row equalled. The guide number system underlying that table drove

1701:

placed over the flash device or are lens filters on the camera. Flash devices may come with detachable color-correction gels or filters to match the color of the flash with different types of ambient lighting such as incandescent and fluorescent. Some modern flash devices can even detect when

3429:

the sunlit ones. For any given shutter speed, a flash device can only fill shadows to 50% the contribution from the sun out to a certain distance; at a camera's X‑sync shutter speed, no change in ISO sensitivity—and accompanying f‑stop setting—can influence this proportional

2405:

If one wanted the benefit of all the light produced by a flashbulb (highest possible guide number), relatively long exposure times were required because most flashbulbs didn't stop producing useful amounts of light until 20–90 milliseconds (ms) after electrical current was applied. The GE

1372:

reciprocal relationship breaks down when on-camera flash devices that are set to full or near-full power are used in combination with cameras set to very high ISO sensitivities and large apertures (exceedingly long distances). ISO settings like 102,400 can yield guide numbers in excess of

108:

This simple inverse relationship holds true because the brightness of a flash declines with the square of the distance, but the amount of light admitted through an aperture decreases with the square of the f-number. Accordingly, as illustrated at right, a guide number can be factored to a

5034:

Note that Kodak's exposure guidelines—for photographs taken in typical settings without the benefit of incident-light meters—are for pictures shot during a broad portion of the day with even some light haze in the sky; this is half as bright as the clear-sky, near-noon, open-area,

1119:

Unfortunately, the optics of flash heads are complex; each manufacture's designs not only have illumination areas that are slightly different, but are the product of differing relative proportions of transmission, diffusion, reflection, and refraction among their optical elements

634:

to the subject; if the flash device is detached from the camera, the position of the camera is irrelevant. Furthermore, unless a flash device has an automatic zoom feature that follows the setting of a camera's zoom lens, guide numbers do not vary with the focal length of lenses.

3828:

each, from one distance to the next (6, 9, 12, 18, and 24 feet) so each step would be accompanied—by definition—by an increase in aperture of precisely one f‑stop. Not surprisingly, the data scatter was as tight as mathematical rounding to the nearest foot permitted.

3484:

for the smaller. However, apparently assuming photographers using their product would be doing so in a relatively narrow range of distances common to portraiture, made no mention of flash-to-subject distance. The instruction sheet then directed the photographer as follows:

3516:

innovation, photographers and publications—via tedious trial and error with different flashbulbs and reflectors—generated tables providing a large number of aperture-distance combinations. For instance, a 1940 edition (written too late to incorporate guide numbers) of the

2422:

photoflash triggering, which gave M bulbs a head start by delaying the opening of the shutter so any given camera's fastest exposure time would be centered at the 20 ms point (an 18.75 ms delay for instance, for a definitional camera capable of

898:

The mathematical relationship between guide numbers and power levels can also be understood using the below alternative formula, which is suitable whenever the numerator in the fractional power setting is 1 (which is usually the case with flash devices):

2497:

second exposure. This relationship between shutter speed and guide number was reflected in the guide number tables printed on flashbulb packaging after the industry-wide adoption of the guide number system, as exemplified by the below-left table for the

3424:

Note that increasing the ISO sensitivity of a digital camera (or choosing a faster film speed) will not increase the distances given in these tables because the extent to which ISO sensitivity affects the exposure in the fill-flash areas of an image

2340:

Conversely, longer exposures also have no effect on guide number. After the flash has extinguished, longer shutter speeds will only increase the contribution from continuous ambient light, which can lead to ghosting with moving subjects. See also

4251:

had tighter sync timing tolerances during the flashbulb era because their cameras were used by demanding professionals in disciplines where there was often significant economic consequences to underexposures with flashbulbs at fast shutter

4265:

The continuous-light exposures underlying the above tables are in accordance with Eastman Kodak Company's guidelines for exposing film. For example, as exemplified by the technical data sheet for their Kodak Professional Ektar 100 film

2363:

due to their relatively long flash durations. Vintage flashbulbs, though no longer made, are still available and have a niche following, largely because even medium-size bulbs such as the once-popular General Electric Synchro-Press

2077:

instance, if a polarizing filter attenuates by 1 f‑stop and the flash device is set to ISO 100, then the camera can simply be set to ISO 200. The extra camera sensitivity compensates for the loss due to the filter.

638:

Note that manufacturers of flash devices may provide guide numbers ratings specified relative to ISO 200, which increases them by the square root of the difference, or a 41 percent increase relative to those given at ISO 100. See

4207:

Even with TTL, non-average scenery such as off-center subjects with distant backgrounds or scenery with elements that have non-average reflectance can confound TTL metering. However, such situations cannot confound guide number

89:) of photoflash devices (flashbulbs and electronic devices known as "studio strobes", "on-camera flashes", "electronic flashes", "flashes", and "speedlights") is a measure photographers can use to calculate either the required 5556:

With the indicator set to B, the shutter opens when the bulb is pressed and remains open as long as the pressure is maintained (“bulb” exposure), a very convenient means of making time exposures of only a few seconds'

4016:

In the context of photography, is the measure of the total energy, or quantity, of eye-adjusted visible light that impinged upon a unit area over a specified period of time. In common vernacular, it is the product the

5046:", which is EV 15 at ISO 100, or 81,900 lux. Notwithstanding differences in the assumed daylight illuminance, a proper continuous-light exposure is still governed by the same mathematical relationship where 791: 3458:

This compelling new way of easily and accurately calculating photoflash exposures was quickly adopted by manufacturers of a wide variety of photographic equipment, including flashbulbs, film, cameras, and flashguns.

266:

to eliminate ambiguity as to which length-based system of measurement underlies the guide numbers. As with metric-based guide numbers, foot-based guide numbers are a two-factor unit of measure except the units are

288:

It is easy to use guide numbers to calculate either an aperture or a flash-to-subject distance. Consider a flash device with a rating of 28 meters (which might be marked "92 feet", "28 DIN", "28/92", "92", etc.).

5911:

is a dedicated TTL flash for use with Pentax & Samsung DSLR, mirrorless or point-and-shoot cameras. The VS-510 features a guide number of 141' at ISO 100 and an adjustable tilt head with five positions: 0 to

1017: 653:

Most modern electronic flash devices have manually adjustable power settings. Moreover, virtually all modern on-camera flash devices that have manually adjustable power settings also provide either a built-in

5728:

One notable way of expressing guide numbers scaled for use with both feet and meters (and relative to an ISO setting of 100) is as practiced by Metz mecatech GmbH, as exemplified by the data sheet for their

4197:

Another not-uncommon marketing practice is to rate flash devices for a coverage angle suitable for use with a 35 mm-format, full-frame lens with a 35 mm focal length (a flash coverage angle of 60°

4235:. By the 1980s, when exceedingly few serious hobbyists or professionals were still using flashbulbs, some camera repair centers had very loose adjustment specifications for consumer-grade cameras, such as 2638:, allowed extraordinary flexibility with shutter speeds, ranging from the slowest speeds on the dial to the fastest where only a narrow slit passed over the film—at the expense of course, of guide number. 5855: 5849:

The style for expressing guide numbers throughout the metric-observing world is typified by the practices of Metz mecatecheh GmbH, as exemplified by the German-language version of their website for their

2626:

of a second (67 ms) to obtain an even exposure across the entire image area—and a not-insignificant boost in the guide number by capturing all the luminous energy to the left of the 20 ms peak.

1688:

Note B: The ISO sensitivities shown in this table are their common nomenclature values; their actual underlying values may be slightly different, such as ISO 250, which is actually approximately 252.

2665:

of a second; such a relatively long exposure requires particularly small apertures and/or low ISO sensitivities, both of which constrain how far a camera and its on-camera flash can be from the subject.

5663: 4226:

During the heyday of flashbulbs (post-WWII to the late 1960s), adjustment tolerances for the sync timing of camera shutters varied; each manufacturer had their own specifications and tolerances. Though

2457:

of a second, would close its shutter 59 ms after triggering a flashbulb (18.75 ms + 40 ms = 58.75 ms) and would achieve the maximum rated guide number from the

4887: 4819: 4751: 4683: 1104:

cameras. Manufacturers' advertising practices vary as to the angle of coverage underlying their guide number ratings, in large part because some flash devices can be zoomed whereas others are fixed.

6012:, Vol. 3 (1939), p. 17. Note that the article title on page 20 was "SIMPLIFIED FLASH EXPOSURE TABLES" and, using GE's early terminology, referred to guide numbers as "Flash Numbers" (in title case). 5139: 1793: 4383: 93:

for any given flash-to-subject distance, or the required distance for any given f‑stop. To solve for either of these two variables, one merely divides a device's guide number by the other.

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between a flash device and a scene, such as light-colored ceilings, do have an influence. Guide numbers are often calculated by manufacturers for optimum results in average indoor settings. See

135:

became available in the late 1930s, has become nearly superfluous due to the ubiquity of electronic photoflash devices featuring variable flash output and automatic exposure control, as well as

2171: 4145:

Bold typestyle is not a required convention for denoting guide numbers. Bolding is consistently used throughout this article to unambiguously distinguish the text and measures being discussed.

1327:

Particulates and aerosols typically present in outside air limit the extent to which high guide numbers created by high ISO sensitivities can be used to illuminate scenes at long distances.

5468: 4120:-mounted flash devices, at ISO 100, 60° horizontal coverage angle (suitable for use with a 35 mm-format, full-frame lens with a 35 mm focal length), and full power, the Holga 1368:

Note that the extremely high guide numbers shown in the right-hand portion of the table have a limited real-world ability to extend flash distances. As the above photo illustrates, the

3982:

In the context of photography, is the measure of the intensity, or concentration per unit area, of eye-adjusted visible light impinging upon a surface. In common vernacular, it is the

3841:

The system I use is to decide upon lens opening (as demanded by depth of field) and, working with the guide number of the bulb, figure out how far the flash should be from the subject.

2368:

had huge light outputs on the order of 23,000 lumen⋅seconds—far exceeding the most powerful of today's hot shoe-mounted electronic flash devices. At a relatively slow shutter speed of

5272: 661:

Nevertheless, for those who want to master the math, guide numbers diminish from their full-power ratings as the square root of their fractional setting per the following formula:

5275:

than their indoor-rated guide numbers indicate in order to obtain a full-rated luminous exposure. The above fill-flash tables give distances that have been adjusted accordingly.

4956: 4626:

When utilizing fill flash, where balancing flash and continuous light can be difficult, the following four derivatives of this continuous-light exposure equation can be useful:

658:(such as shown in the photo at the top of this article) or a digital display that automatically shows the effect power levels have on f‑stop and distance (guide number). 5388: 2232:

button on a scientific calculator), which is approximately 2.5198, and then multiply that by 100, which equals about 252. The nearest standard camera setting is ISO 250.

217:

and require guide numbers scaled accordingly. To serve the U.S. market, manufacturers of flash devices typically provide foot-based guide numbers and add nomenclature such as

23:

A scene will be properly illuminated for every combination of f‑stop and distance shown on this flash device's exposure calculation dial, each of which equals the same

5505: 5641: 5422: 4532: 4217:

A notable exception to this generality is when a flash device at full power is used in combination with cameras equipped with leaf shutters set to very brief exposure times.

303:, and wants to know the required flash-to-subject distance; he merely divides the guide number by 4. Thus, a subject 11 meters or 36 feet away will be correctly illuminated 3407:

of a second, is shopping for a flash device, and desires the capability to fill shadows from up to 2.5 meters (8 feet) away, a flash device with a guide number of at least

3826: 2410:

flashbulb for instance, was a Class M (medium peak) bulb, which were designed to produce peak luminous fluxes 20 ms after firing (see the graph at lower right). The

1884: 1085: 885: 4231:

could be expressed to arbitrary precision such as hundredths of a millisecond (tens of microseconds), practical manufacturing with mechanical shutters did not have such

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because the sun is such a bright, unadjustable light source against which a flash device must compete. However, a contributing factor is that many modern cameras with

5812: 2230: 1856: 1348:

to favor distance, the utility pole marked by the arrow would be properly illuminated were it not for haze glare, which fogged the image and diminished brightness.

333:

Alternatively, if one has an established flash-to-subject distance and wants to find the required f-number, one divides the guide number by the distance. Example:

4909:

For any combination of lighting, film, and camera settings that conforms to one of the above five equations, a proper luminous exposure is calculated as follows:

2394:

at ISO 100 when using a typical 6- or 7-inch-diameter (150–175 mm) polished reflector. With peak powers often between one and two million lumens, many young

2195: 1817: 1043: 839: 817: 5754: 2268:

flashbulb is shown here. Like all Class M (medium peak) bulbs, its peak output was defined as occurring 20 milliseconds after applying electrical current. The

6166: 5076:

are slightly different from those for continuous-light exposures. Kodak calculates exposures for electronic flash devices according to the following formula:

4433: 4426: 4274: 543:

affect guide numbers because, by definition, choosing a different value for one factor is automatically accompanied by a reciprocal adjustment in the other.

2244:

With focal-plane shutters, exposures faster than the X-sync speed can cause the image area to be partially obscured by the closing curtain during the flash.

7752: 5609:

The original table used the common nomenclature values for the apertures; the guide numbers shown here are based on the precise aperture values from the

547:

adjustments. Manual attenuation settings are usually steps in powers of 0.5 (full f‑stops) that commonly extend five to eight f‑stops deep

5532:

bulbs. The Sashlite flashbulb was introduced at a time when the equipment typically used for professional indoor portraiture was a large-format studio

4321:, and so forth. Kodak's guidance for a proper continuous-light exposure for all film speeds, scene illuminance, and camera settings reduces as follows: 5915:

Another notable example of how flash device guide numbers are communicated to the U.S. market is the large retailer, B & H Foto & Electronics (

3522:

the guide number values in each column; the data for the right-most flashbulb setup has over a three-quarter f‑stop variation from high to low.

1131:

The below table illustrates the variation in guide numbers depending on zoom level for some select, relatively high-power zoom-capable flash devices.

7699: 4270:), scenes that are lit by bright or hazy sun with distinct shadows and which are shot between 2 hours after sunrise and 2 hours before sunset are an 2465:

So long as one used flashbulbs with leaf shutter-type cameras, faster exposures and larger apertures could be used to minimize motion blur or reduce

210:

As such, guide numbers can be reduced either to distance in meters or to f‑stops depending on how one uses the guide number in a calculation.

5734: 5981: 3832:

By late 1949, authors catering to hobbyists were using guide numbers in articles in a routine fashion, as exemplified by the January 1950 issue of

241:

guide numbers—which can be expressed in a variety of formats—so distances and f‑numbers may be calculated using either feet or meters, e.g.

667: 3454:

General Electric introduced the guide number system in 1939 concurrently with the introduction of a compact, wire-filled flashbulb called the

2630:

A notable exception to this limitation with focal-plane shutters was when using FP sync in combination with "flat peak" (FP) bulbs, which had

5778: 585:

Shutter speeds do not factor into guide number calculations with electronic flash and, for the most part, have no effect on exposures. See

1386:

results only by either positioning the flash device off-axis from the camera by a fair distance or by shooting at the smallest apertures.

7742: 7694: 96:

Though guide numbers are influenced by a variety of variables, their values are presented as the product of only two factors as follows:

5749:

Another notable example is Nikon's practice for expressing the technical specifications of products marketed in the U.S., such as their

5211:, which equals 0.981 lux⋅second at a distance of one meter). This slightly reduced flash exposure (versus the continuous-light value of 905: 7479: 2437:

stopped producing useful amounts of light roughly 50 ms after current was applied. Thus, a camera with a fastest shutter speed of

1329:

This photo was shot in fair quality air at ISO 12,800 using a modestly powerful camera-mounted flash, yielding a high guide number of

4176:

of the objects being photographed) have no influence on the illuminance (lux value) arriving at any given scene, reflective surfaces

1827:(it is irrelevant if it is scaled for meters or feet for this purpose) and the rated filter loss is 1.5 f‑stops. Take 0.5 and 480:

subtended by the circular- or rectangular-profile beam as it leaves the flash head (the average of the beam's X- and Y-axis angles).

6344: 4825: 4757: 4689: 4632: 1365:

The below table shows the proportional change in a flash device's guide number relative to both ISO 100 and ISO 200.

6450: 6197: 5965: 5710: 5283:

smaller f‑number) by one f‑stop. Those larger apertures, when expressed in industry-standard nomenclature, are

5083: 1722: 4327: 1362:

specified relative to ISO 200, which increases its guide number by 41 percent relative to those given at ISO 100.

7747: 2447:

of a second (one that began exposures 18.75 ms after a bulb was fired with M sync triggering), and which was set to

2086: 1087:

button on a calculator), which equals approximately 5.657. Divide 51 by 5.657 to obtain a reduced-power guide number of

276:

To convert a guide number given in meters to feet, divide by 0.3048. To convert a guide number given in feet to meters,

7689: 7241: 4107:, which is an absolute measure of illuminating power but is not particularly useful for calculating exposure settings. 3450:. The pneumatic shutter release cords of the era featured rubber bulbs the photographer squeezed to take a photograph. 7450: 6106: 5188:

This formula means that under the same conditions used above for Kodak Professional Ektar 100 film (ISO 100 and

4267: 7417: 6161: 4423: 4271: 5427: 2205:

f‑stops and the flash device is set to ISO 100. Take 2 and raise it to the power of 1.3333 (using the

7709: 7203: 1716:

Guide numbers diminish as the square root of filter attenuation in f‑stops, as per the following formula:

1710: 607: 4132:

have guide numbers of 36 (m). And still under the same conditions, the side-mounted pistol grip-style Metz

7825: 7382: 6865: 6652: 3791:

By 1941, two years after GE introduced the guide number system, guide number ratings for products like the GE

3470:" and to set their shutter to either "Bulb" or "Time". The instruction sheet further suggested an aperture of 2634:

rise times followed by broad, relatively level plateaus in their light output curves. The FP bulbs, like GE's

7291: 7223: 6976: 6498: 185: 5892:(foot symbol) when marketing in the U.S. is as practiced by Bolt, which specifies the guide number of their 5230: 3850:

concept in 1939, General Electric initially referred to the new system as "Flash Numbers". Two years later,

1709:(TTL), guide numbers must be manually compensated for the effect of on-lens filters. For instance a typical 845:

The following is a step-by-step example of using the above formula: Suppose your full-power guide number is

7719: 7714: 5787: The maximum Guide No. is approximately 141.1 ft./43m at ISO 100 and 105 mm flash coverage. 4159:

and don't misleadingly appear to be units of measure for length with their accompanying numeric magnitudes.

1713:, which attenuates 1–1.5 f‑stops, will diminish guide numbers to 71–60% of their unfiltered rating. 7724: 7001: 6503: 5215:) compensates for reflections off light colored ceilings, which is typical for indoor flash photography. 3400:

As can be seen by referring to the above tables, if a photographer has a camera with an X-sync speed of /

1702:

color-correction gels have been attached and automatically compensate for their effect on guide numbers.

4915: 7820: 7455: 7143: 7046: 6339: 5916: 5354: 1314:

Note A: Flash angle is equivalent to the denoted lens focal length for a full-frame 35 mm camera.

849:(it is irrelevant if it is scaled for meters or feet for this purpose) and the flash device is set to 7422: 7372: 7332: 7185: 7071: 7021: 6713: 6657: 6513: 6265: 6190: 4417: 3945:, of eye-adjusted visible light emitted over a period of time. In common vernacular, it is the total 2616:

for instance, a modern camera with a focal-plane shutter and X sync would require a shutter speed of

1706: 5473: 2360: 400:

Suppose a photographer's flash-to-subject distance is 9.75 meters (32 feet) and the guide number is

132: 7623: 7218: 6946: 6738: 5612: 5393: 4503: 2279:

of 23,000 lumen⋅seconds is the shaded area to the right of the definitional shutter opening point (

7588: 7392: 7296: 7160: 7011: 6843: 6748: 6391: 6309: 6275: 5958:

Focal Encyclopedia of Photography: Digital Imaging, Theory and Applications, History, and Science

3807: 1865: 1823:

The following is a step-by-step example of using the above formula: Suppose your guide number is

1066: 866: 4239:

for M sync, which averaged 18.5 ms. Manufacturers of professional studio cameras like

7830: 7799: 7643: 7618: 7427: 7412: 7347: 7327: 7233: 7155: 6986: 6905: 6900: 6875: 6803: 6793: 6743: 6733: 6667: 6630: 6558: 6533: 6131: 5544:

in its tray. Advanced hobbyists in 1909—decades before the first flashbulbs—could buy portable

4313:—a film speed of ISO 200 is properly exposed when a scene receives a luminous exposure of 4232: 4035: 3990: 258:

Though nomenclature conventions such as these can make guide numbers misleadingly appear to be

131:

The guide number system, which manufacturers adopted after consistent-performing mass-produced

78: 5702: 5695: 2402:) for minutes after having their pictures taken at close distance with flashbulbs of the era. 7704: 7499: 7407: 7402: 7387: 7377: 7352: 7337: 7198: 7131: 7101: 7061: 6971: 6961: 6798: 6677: 6640: 6563: 6041: 5518: 5178: 4185: 4055: 2419: 2415: 2343: 2308: 200: 7256: 4281:(EV 14 @ ISO 100). For this illuminance, Kodak recommends settings (ISO 100, 1705:

Unless a hot shoe-mounted electronic flash device's power can be controlled by a camera via

655: 7788: 7397: 7367: 7362: 7357: 7342: 6996: 6915: 6885: 6838: 6783: 6773: 6698: 6523: 6470: 6183: 2252:

A Leica "CEYOO"-model flashgun with folding reflector (1950–1959), which accepted "Midget"

2208: 1834: 1116:—given at their most zoomed setting and not all flash devices can zoom to the same extent. 8: 7494: 7467: 7437: 7091: 7006: 6910: 6788: 6768: 6758: 6753: 6723: 6615: 6528: 6356: 6351: 4050: 3902: 2652: 2303: 528: 496:

The above variables fall into two classes that influence the magnitude of guide numbers:

463:) emitted by the flash head (which is itself the product of the duration and the average 75: 4302:. This exposure level applies proportionally across the full gamut of Kodak's color and 7638: 7301: 7251: 7076: 6931: 6890: 6870: 6808: 6763: 6728: 6703: 6260: 6225: 5975: 5525: 2201:

Here is a step-by-step example of using this formula: Suppose a filter attenuates by 1/

2180: 1802: 1028: 824: 802: 6099:

Understanding Flash Photography: How to Shoot Great Photographs Using Electronic Flash

7608: 7544: 7531: 7462: 7126: 7051: 7041: 7031: 7016: 6880: 6848: 6708: 6543: 6314: 6102: 6035: 5961: 5706: 4303: 2483:

of a second still diminished its guide number, though it still managed an impressive

887:

button on a calculator), which equals 0.25, and multiply that by the guide number of

27:. The guide number here (full power setting, ISO 100, and normal-angle coverage) is 6141: 5680: 3506:

introduced their very successful, golf ball-size, wire-filled, bayonet-base, Midget

1886:

button), which equals approximately 0.595, and multiply that by the guide number of

237:. Another common practice when flash devices are marketed in the U.S. is to provide 124:) because they are influenced by other variables, notably the camera's ISO setting ( 7663: 7613: 7571: 7556: 7539: 7509: 7504: 7148: 7106: 7056: 6818: 6778: 6718: 6573: 4045: 193: 7759: 7668: 7576: 7193: 6941: 6823: 6518: 6465: 6460: 6428: 6413: 6371: 6170: 4437: 4430: 4278: 3913: 2399: 2316:

speed faster than the camera's rated X‑sync speed, which is often between

121: 5552:, which devoted three pages to the features and operation of Conley's shutters: 7445: 7271: 7213: 6981: 6662: 6568: 6553: 6548: 6443: 6250: 6240: 6230: 5897: 5889: 5545: 5278:

Also bear in mind that the distances given in the above tables do not obey the

4040: 2466: 1828: 226: 197: 136: 6151: 5773:

Yet another notable example is Canon USA's practices, as exemplified by their

1323: 1100:

degrees but are often expressed as being equivalent to lens focal lengths for

455:

The magnitude of guide numbers is a function of the following four variables:

7814: 7598: 7566: 7551: 7516: 7276: 7121: 7086: 6672: 6645: 6625: 6593: 6538: 5036: 4124:

has a guide number of 6.5 (m). Under the same conditions, both the Sony

3864: 2248: 464: 439: 7036: 188:) is observed, guide numbers are expressed as a unitless numeric value like 120:

Guide numbers are not an absolute measure of flash power (a property called

19: 7764: 7658: 7653: 7648: 7603: 7489: 7484: 7138: 6858: 6828: 6605: 6588: 6433: 6255: 6245: 6235: 5941: 5541: 4244: 3933: 3893: 3443: 2395: 2272:

had a peak luminous flux of 1.8 million lumens. Its rated luminous energy,

1858:

button on a scientific calculator), which equals roughly 0.35355. Take the

1394:

CHANGE IN GUIDE NUMBERS AS ISO SENSITIVITY VARIES FROM AN ADVERTISED RATING

1125: 460: 786:{\displaystyle Full\ power\ GN\times {\sqrt {{y}/{x}}}=Reduced\ power\ GN} 7769: 7633: 7628: 7561: 7474: 7311: 7286: 7116: 7111: 7096: 6951: 6833: 6813: 6682: 6583: 6475: 6438: 6408: 6361: 6329: 6324: 6285: 6206: 5533: 5204: 4974: 4401: 4104: 3953: 3438: 2260: 1859: 1101: 860: 623: 599: 595: 505: 477: 214: 6158: 5324:

but have the following more precise values underlying the above tables:

3941:

In the context of flash devices, is the measure of the total energy, or

539:

Changing either the f‑stop or the flash-to-subject distance does

7281: 7261: 7175: 7165: 7026: 6991: 6966: 6895: 6635: 6620: 6600: 6482: 6418: 6334: 6280: 5919:), which states guide numbers formatted like this example for Nissin's 5537: 4240: 4078:

The Nikon brand name for its camera-mounted electronic flash products,

3467: 3463: 3447: 2647: 532: 156: 125: 6128: 2337:

darker towards the left or bottom, as seen in the photo at top right.

576:

To calculate how reductions in power levels affect guide numbers, see

168:. Guide numbers may be expressed in either of these units of measure: 160:

Guide numbers are a composite unit of measure comprising two factors:

7673: 7246: 7208: 7170: 7066: 6956: 6423: 6386: 6381: 6366: 6319: 6302: 6122: 4060: 4021:

of light measured at the surface of a photographic subject times the

2299: 2256:

flashbulbs. The blue coating (type 5B) permitted use with color film.

2240: 1698: 1121: 617: 517: 3442:

Before the introduction of flashbulbs, photographers used magnesium

2469:

at the expense of guide number. In the case of the GE Synchro-Press

7266: 7081: 6578: 6508: 6376: 6297: 6292: 4157:

notations as to the measurement system underlying the guide numbers

4117: 4087: 330:, the light source must be 5.5 meters or 18 feet from the subject. 90: 6059:(16th ed.). Boston: American Publishing Co. pp. 313–314. 5072:

Importantly, Eastman Kodak Company's exposure recommendations for

4090:-mounted electronic flash devices while Canon uses the trade name 1012:{\displaystyle Full\ power\ GN\div {\sqrt {x}}=Reduced\ power\ GN} 213:

In the U.S. however, photographers typically measure distances in

7306: 6455: 6401: 5524:

When Sashalite's instructions mentioned setting a shutter to its

5208: 4248: 3502: 370:. The flash device must be 10 meters (33 feet) from the subject. 292:

Suppose a photographer has a flash device with a guide number of

3901:

In the context of flash devices, is the measure of the power of

6853: 6270: 6220: 6143:

Understanding Flash Guide Numbers, plus guide number Calculator

5169:

is ISO arithmetic speed or sensitivity (e.g. 100, 200, and 400)

4173: 3462:

The first flashbulb was introduced in 1925 and was filled with

3044:

FILL SHADOWS TO ONE F‑STOP LESS THAN THE SUNLIT PORTIONS

2681:

FILL SHADOWS TO ONE F‑STOP LESS THAN THE SUNLIT PORTIONS

1198: 6175: 5807:

ratings when providing the technical specifications for their

7521: 6936: 6396: 5937: 5563: 3042:

DISTANCE FOR A GIVEN GUIDE NUMBER AT WHICH A FLASH DEVICE CAN

2679:

DISTANCE FOR A GIVEN GUIDE NUMBER AT WHICH A FLASH DEVICE CAN

5571:, as well as in instruction manuals for products like their 5226:

settings, flash devices must be roughly nine-percent closer

4155:

symbols for length within parentheses, it is clear they are

2398:

chased after fairylike retinal bleached spots (a symptom of

1697:

Filters reduce guide numbers regardless of whether they are

6148: 6138: 6118: 5528:, the company was not referring to glass flashbulbs but to 5219:

Outdoors mixing of continuous-light and GN-based fill flash

3986:

of light measured at the surface of a photographic subject.

3524: 3035: 2672: 2504: 1899: 1388: 1133: 4905:

to obtain the denominator of the fractional shutter speed)

4882:{\displaystyle {\frac {{f^{2}}\cdot {k}}{E_{v}\cdot S}}=t} 4814:{\displaystyle {\frac {{f^{2}}\cdot {k}}{t\cdot S}}=E_{v}} 4746:{\displaystyle {\frac {{f^{2}}\cdot {k}}{E_{v}\cdot t}}=S} 4678:{\displaystyle {\sqrt {\frac {E_{v}\cdot t\cdot S}{k}}}=f} 2306:), shutter speed has no effect on guide numbers. See also 359:

Suppose a photographer wants to shoot with an aperture of

6084:. Butler & Tanner Ltd., Frome and London. p. 84. 4978: 4405: 3973: 3882: 2641: 2473:

with M sync for instance, shutter speeds as long as

2302:

technology are used with most modern cameras (those with

509: 486:

Filters (either on the flash or on the camera lens). See

2359:(and still do today) influence guide numbers when using 2197:

equals the camera filter's rated loss in f‑stops.

337:

and the distance is 6 meters; one needs and aperture of

5134:{\displaystyle GN={\sqrt {\frac {BCPS\times ISO}{20}}}} 4422:). A table of lux values vs. EV @ ISO 100 is available 3046:(SUNLIGHT = EV 14 AT ISO 100, GUIDE NUMBERS AT ISO 100) 2683:(SUNLIGHT = EV 14 AT ISO 100, GUIDE NUMBERS AT ISO 100) 2080:

The formula governing this relationship is as follows:

1788:{\displaystyle GN\times {\sqrt {0.5^{n}}}=Filtered\ GN} 1354:

greater ISO sensitivity yields a greater guide number.

1094: 1045:

is the denominator in the fraction of the power setting

841:

is the denominator in the fraction of the power setting

323:= 36 ft). For the same guide number and an aperture of 5615: 5476: 5447: 5430: 5396: 5357: 5233: 4506: 4378:{\displaystyle {\frac {E_{v}\cdot t\cdot S}{f^{2}}}=k} 516:; namely its power setting, flash coverage angle, and 184:

Throughout most of the world where the metric system (

6153:

EV – Exposure Value (with EV table and EV calculator)

5877:• High max. guide number 76 at ISO 100/21° and 105 mm 5744:• High max. guide number 52 (meters), High max. guide 5681:

Understanding Flash Guide Numbers, plus GN Calculator

5575:. "Brief time" was also used in reference works like 5175:

Characterizing the Output of Photographic Flash Units

5086: 4918: 4828: 4760: 4692: 4635: 4330: 4182:

Characterizing the Output of Photographic Flash Units

3810: 2655:

can sync with flash devices at speeds no faster than

2211: 2183: 2089: 1868: 1837: 1805: 1725: 1069: 1031: 908: 869: 827: 819:

is the numerator in the fraction of the power setting

805: 670: 3862: 2289:

of a second before the point of peak luminous flux).

1897:

The below table provides some common filter values.

630:

Guide number distances are always measured from the

523:

Those that affect the camera's non-aperture-related

35:

for feet (orange). For instance, on the foot scale,

6061:

Revised and largely re-written by Sowerby, A. L. M.

3909:

at which a flash device emits light during a flash.

31:for calculations made in meters (yellow arrow) and 5865:• Hohe max. Leitzahl 76 bei ISO 100/21° und 105 mm 5694: 5635: 5499: 5462: 5416: 5382: 5266: 5133: 4950: 4881: 4813: 4745: 4677: 4526: 4377: 3820: 2224: 2189: 2166:{\displaystyle Flash\ ISO\times 2^{n}=Camera\ ISO} 2165: 1878: 1850: 1811: 1787: 1608:Proportional change in GN relative to ISO 200 1529:Proportional change in GN relative to ISO 100 1079: 1037: 1011: 879: 833: 811: 785: 504:of a flash arriving at a scene (a property called 395: 233:′ ) to unambiguously denote that fact, e.g. 4262:The continuous-light portion of fill-flash photos 1819:equals the filter's rated loss in f‑stops. 1049:Example: Suppose your full-power guide number is 859:power. Divide 1 by 16 to obtain 0.0625. Take the 354: 283: 7812: 6101:, (paperback – August 30, 2011), Amphoto Books, 4103:Studio strobes in particular are often rated in 3804:slightly finer increases, averaging a factor of 4298:of a second) that equal a luminous exposure of 3905:being emitted. In common vernacular, it is the 2670:hours after sunrise and 2 hours before sunset. 2264:The photometric output of the GE Synchro-Press 192:, even though they are technically a composite 5069:Flash exposures vs. continuous-light exposures 1140:VERSUS FLASH ANGLE (NORMALIZED TO 105 mm) 641: 335:Guide number = 48 (m) 146: 6191: 5595:G⋅E MAZDA Mighty Midget Photoflash Lamp No. 5 5463:{\textstyle {\sqrt {2}}^{\ 5{\tfrac {1}{3}}}} 4469:is ISO arithmetic speed or sensitivity (e.g. 3949:of light released over the course of a flash. 587: 578: 5980:: CS1 maint: multiple names: authors list ( 5746:number 170 (feet) for ISO 100/21° and 105 mm 5517: 1318: 115:large f‑number times a short distance 7743:Conservation and restoration of photographs 6082:Newnes Photographers' Pocket Reference Book 5577:Newnes Photographers' Pocket Reference Book 2433:second exposures, or 2.5 ms). The GE 2235: 648: 602:and duration of a flash (a property called 500:Those that affect the non-distance-related 111:small f‑number times a long distance 70:× 1.7 m and every combination between. 7480:Comparison of digital and film photography 6198: 6184: 6005: 6003: 5960:(4th ed.). Focal Press. p. 769. 5674: 5672: 891:to obtain a reduced-power guide number of 443:An incident-light meter measures the true 424:In U.S. customary units: GN 128 ÷ 32 ft = 7700:Photographs considered the most important 6033: 5926:• Guide Number: 197' at ISO 100 and 200mm 6133:Flash Photography ~ History & ILFORD 6054: 5951: 5949: 5799: 5797: 5795: 5692: 4082:, is frequently used in lowercase form ( 3437: 2293: 2259: 2247: 2239: 1322: 1142:WITH SELECTED ZOOM-CAPABLE FLASH DEVICES 594:Guide numbers are not affected by scene 438: 155: 18: 6000: 5869:This translates to English as follows: 5811:, one of which is relative to ISO 200 ( 5669: 5267:{\textstyle ({\sqrt {270/328}}=90.7\%)} 2509:EFFECT OF SHUTTER SPEED ON GUIDE NUMBER 2298:When electronic flash devices based on 1063:power. Take the square root of 32 (the 16:Photoflash exposure setting measurement 7813: 6079: 6040:. Camera Craft Publishing Co. p. 5724: 5722: 2642:Fill flash: Guide numbers vs. distance 2511:FOR THE GE SYNCHRO-PRESS #11 FLASHBULB 2378:of a second (40 milliseconds), the GE 598:. Guide numbers are a function of the 488: 6179: 5988: 5955: 5946: 5905:VS-510P Wireless TTL Shoe Mount Flash 5792: 5701:(9th ed.). Focal Press. p. 3784:Bear in mind that the above table is 3477:for Sashalite's larger flashbulb and 1890:to obtain a filtered guide number of 473:, below for illumination terminology. 5599:General Electric Sure•Fire Number 5. 3988: 3795:were being discussed in books like 3534:Complete Introduction to Photography 3519:Complete Introduction to Photography 1692: 1095:Effect of flash angle (zoom setting) 7695:Museums devoted to one photographer 5719: 5026:is luminous exposure in lux⋅seconds 151: 13: 7242:Timeline of photography technology 6163:EV/Lux/FootCandle Conversion Chart 6091: 5661:B & H Foto & Electronics: 5573:1 & 1A Pocket "Kodaks" Juniors 5258: 5001:is exposure time in seconds (e.g. 4951:{\displaystyle E_{v}\cdot t=H_{v}} 4447:is exposure time in seconds (e.g. 3911: 2350: 1138:VARIATION IN DECAY OF GUIDE NUMBER 102:Guide number = f-number × distance 14: 7842: 6112: 5830:20°C/68°F) to 48 m/157.5 ft. 5764:34.5 m/113 ft. (at 35 mm) 55 5383:{\textstyle {({\sqrt {2}}}^{\ 7}} 4500:. Common f‑stops from the 2513:(6- OR 7-INCH POLISHED RELFECTOR, 384:In U.S. customary units: GN 92 ÷ 7793: 7783: 7782: 6057:Wall's Dictionary of Photography 5856:product page specifications here 3801:Wall's Dictionary of Photography 1053:and your flash device is set to 296:, sets the camera's aperture to 262:units of measure, they serve as 7794: 6205: 6073: 6064: 6048: 6027: 6015: 5931: 5882: 5603: 5583: 5511: 5500:{\textstyle {\sqrt {2}}^{\ 5})} 4255: 4220: 4211: 4201: 4191: 4162: 4148: 4139: 396:Example for finding an aperture 42:× 30 ft = 120, as do both 5843: 5836:standard illumination pattern, 5766:m/180 ft. (at 200 mm) (FX 5686: 5655: 5636:{\textstyle {\sqrt {2}}^{\ n}} 5550:Cameras Photographic Supplies 5494: 5417:{\textstyle {\sqrt {2}}^{\ 6}} 5360: 5261: 5234: 4527:{\textstyle {\sqrt {2}}^{\ n}} 4110: 4097: 4072: 3951: 3494:2. Flash the "Sashalite" bulb. 656:mechanical circular calculator 459:The total luminous energy (in 355:Example for finding a distance 284:Calculating with guide numbers 1: 7292:Painted photography backdrops 7224:Golden triangle (composition) 6499:35 mm equivalent focal length 6055:Mortimer, F. J., ed. (1944). 5768:format, standard illumination 5649: 3799:By 1944, the 16th edition of 3529:1940 EXPOSURE EXPERIMENT WITH 469: 5834:head position, in FX format, 5832:(at ISO 200, 35 mm zoom 5569:Folding Autographic Brownies 3797:Flash in Modern Photography. 3496:3. Close the camera shutter. 483:The ISO sensitivity setting. 415:In metric: GN 39 ÷ 9.75 m = 7: 7002:Intentional camera movement 6037:Flash in Modern Photography 6034:Mortensen, William (1941). 5956:Peres, Michael, R. (2007). 5824:35mm zoom head position, in 5822:34 m/111.5 ft. (at ISO 100, 5803:Nikon, for instance, gives 5664:Understanding Guide Numbers 5161:is beam candlepower seconds 4229:definitional specifications 4029: 3857: 3852:Flash in Modern Photography 3821:{\displaystyle {\sqrt {2}}} 3492:1. Open the camera shutter. 1879:{\displaystyle {\sqrt {x}}} 1080:{\displaystyle {\sqrt {x}}} 880:{\displaystyle {\sqrt {x}}} 610:as their units of measure) 520:in front of the flash head. 147:Understanding guide numbers 10: 7847: 7690:Most expensive photographs 7047:Multi-exposure HDR capture 5280:f‑number × distance 4304:panchromatic B&W films 4136:is rated at 45.5 (m). 3903:eye-adjusted visible light 3433: 3038: 2675: 1391: 1370:f‑number × distance 434: 56:× 7.5 ft. In meters, 7778: 7735: 7682: 7587: 7530: 7436: 7320: 7232: 7184: 6924: 6691: 6491: 6213: 6129:Photographic Memorabilia: 5917:on-camera flash page here 5888:One example of using the 5852:mecablitz 76 MZ-5 digital 5731:mecablitz 52 AF-1 digital 5591:G⋅E MAZDA Synchro-Press 5 4272:illuminance of 40,960 lux 4233:accuracies and precisions 4134:mecablitz 76 MZ-5 digital 4130:mecablitz 64 AF-1 digital 3976:(lumens per square meter) 3846:Upon introducing the new 3527: 3393: 40.1 ft 3390: 37.9 ft 3387: 32.1 ft 3384: 27.3 ft 3381: 23.8 ft 3378: 19.3 ft 3375: 16.1 ft 3372: 13.6 ft 3369: 11.6 ft 2507: 1902: 1707:through-the-lens metering 1319:Effect of ISO sensitivity 1136: 642:Effect of ISO sensitivity 7624:Digital image processing 5693:Jacobson, Ralph (2000). 4493:for an f‑stop of 4317:, ISO 400 requires 4306:where—at 40,960 lux and 4086:) as a generic term for 4066: 3366: 9.6 ft 3363: 8.0 ft 3360: 6.3 ft 3357: 5.3 ft 3354: 4.2 ft 3351: 3.4 ft 2236:Effect of shutter speeds 649:Effect of power settings 588:Effect of shutter speeds 579:Effect of power settings 366:and the guide number is 7297:Photography and the law 6080:Newnes, George (1955). 5781:), which is as follows: 5222:This all means that in 4619:is a constant equaling 3786:for only one film speed 404:. The aperture must be 63:× 26 m = 37 as do 7644:Gelatin silver process 6668:Science of photography 6653:Photographic processes 6631:Perspective distortion 5928: 5914: 5879: 5867: 5840: 5789: 5775:Speedlite 430EX III-RT 5772: 5748: 5637: 5559: 5522: 5501: 5464: 5418: 5384: 5268: 5177:, by Douglas A. Kerr ( 5135: 4952: 4883: 4815: 4747: 4679: 4528: 4489:is the f-number (e.g. 4379: 4184:, by Douglas A. Kerr ( 4036:Exposure (photography) 3848:inverse of the squares 3843: 3822: 3531:FOIL-FILLED FLASHBULBS 3514:inverse of the squares 3498: 3451: 2382:had a guide number of 2290: 2257: 2245: 2226: 2191: 2167: 1880: 1852: 1813: 1789: 1350: 1102:full-frame, 35 mm 1081: 1039: 1013: 881: 835: 813: 787: 533:ISO rating of the film 452: 206:f‑number⋅meters 181: 171:f‑number⋅meters 71: 7826:Photographic lighting 7102:Schlieren photography 6641:Photographic printing 6564:Exposure compensation 5924: 5901: 5871: 5859: 5828:illumination pattern, 5816: 5782: 5770:pattern) (at ISO 100) 5758: 5751:SB-5000 AF Speedlight 5738: 5697:Manual of Photography 5638: 5564:Eastman Kodak Company 5554: 5521: 5502: 5465: 5419: 5385: 5269: 5199:exposure equals only 5136: 4953: 4884: 4816: 4748: 4680: 4529: 4380: 4056:Flash synchronization 3839: 3836:, as follows: 3823: 3488: 3441: 2344:Flash synchronization 2309:Shutter (photography) 2294:With electronic flash 2263: 2251: 2243: 2227: 2225:{\displaystyle x^{y}} 2192: 2168: 1881: 1853: 1851:{\displaystyle x^{y}} 1829:raise it to the power 1814: 1790: 1326: 1082: 1040: 1014: 882: 836: 814: 788: 442: 159: 113:just as readily as a 22: 6886:Straight photography 6524:Chromatic aberration 5809:SB-910 AF Speedlight 5613: 5474: 5428: 5394: 5355: 5231: 5084: 4916: 4826: 4758: 4690: 4633: 4504: 4328: 3808: 2653:focal-plane shutters 2304:focal-plane shutters 2209: 2181: 2087: 1866: 1835: 1803: 1723: 1067: 1029: 906: 867: 825: 803: 668: 451:arriving at a scene. 270:f‑number⋅feet 177:f‑number⋅feet 7753:photographic plates 7438:Digital photography 6616:Hyperfocal distance 6529:Circle of confusion 6024:, April 1938, p. 25 6022:Popular Photography 5995:Popular Photography 5826:FX format, standard 5589:Known variously as 4116:For example, among 4051:Flash (photography) 3867:(or luminous power) 3834:Popular Photography 3427:will equally affect 1156: Vivitar 374:In metric: GN 28 ÷ 7257:Autochrome Lumière 7252:Analog photography 7077:Pigeon photography 6866:Social documentary 6345:discontinued films 6169:2017-08-14 at the 5997:, May 1957, p. 137 5633: 5597:, and after WWII, 5523: 5497: 5460: 5456: 5414: 5380: 5264: 5131: 4948: 4879: 4811: 4743: 4675: 4524: 4436:2017-08-14 at the 4429:2017-08-14 at the 4375: 4277:2017-08-14 at the 3818: 3452: 3421:will be required. 2648:filling in shadows 2418:-type cameras and 2291: 2258: 2246: 2222: 2187: 2163: 1876: 1848: 1831:of 1.5 (using the 1809: 1785: 1351: 1077: 1035: 1009: 877: 831: 809: 783: 549:(power levels of / 453: 182: 72: 7821:Flash photography 7808: 7807: 7609:Collodion process 7545:Chromogenic print 7532:Color photography 7042:Multiple exposure 7017:Lo-fi photography 6544:Color temperature 6119:D. 'n' A. Seaver: 5967:978-0-240-80740-9 5898:product page here 5813:product page here 5779:product page here 5755:product page here 5735:product page here 5712:978-0-240-51574-8 5627: 5622: 5488: 5483: 5455: 5442: 5437: 5408: 5403: 5374: 5368: 5314: 5250: 5129: 5128: 5013: 4871: 4796: 4735: 4667: 4666: 4518: 4513: 4459: 4424:here, by Sekonic. 4367: 4296: 4172:reflectance (the 3991:Luminous exposure 3816: 3782: 3781: 3417: 3413: 3406: 3397: 3396: 3341: 3282: 3266: 3203: 3140: 3034: 3033: 2978: 2919: 2903: 2840: 2777: 2663: 2624: 2609: 2608: 2580: 2569: 2558: 2547: 2536: 2495: 2481: 2455: 2445: 2431: 2414:was intended for 2391: 2387: 2376: 2334: 2324: 2287: 2190:{\displaystyle n} 2153: 2107: 2074: 2073: 1874: 1812:{\displaystyle n} 1778: 1747: 1711:polarizing filter 1693:Effect of filters 1689: 1685: 1684: 1382: 1378: 1338: 1334: 1315: 1311: 1310: 1075: 1061: 1038:{\displaystyle x} 1002: 984: 956: 941: 923: 875: 857: 834:{\displaystyle x} 812:{\displaystyle y} 776: 758: 730: 703: 685: 604:luminous exposure 525:light sensitivity 489:Effect of filters 467:of a flash). See 445:luminous exposure 402:39 (m) / 128 (ft) 294:44 (m) / 144 (ft) 252: 248: 235:Guide number: 92′ 232: 49:× 15 ft and 7838: 7797: 7796: 7786: 7785: 7664:Print permanence 7614:Cross processing 7572:CMYK color model 7557:Color management 7510:Foveon X3 sensor 7505:Three-CCD camera 7149:Miniature faking 7107:Sabattier effect 6719:Astrophotography 6574:Zebra patterning 6200: 6193: 6186: 6177: 6176: 6097:Bryan Peterson, 6086: 6085: 6077: 6071: 6068: 6062: 6060: 6052: 6046: 6045: 6031: 6025: 6019: 6013: 6007: 5998: 5992: 5986: 5985: 5979: 5971: 5953: 5944: 5935: 5929: 5886: 5880: 5847: 5841: 5801: 5790: 5726: 5717: 5716: 5700: 5690: 5684: 5676: 5667: 5659: 5644: 5642: 5640: 5639: 5634: 5632: 5631: 5625: 5623: 5618: 5607: 5601: 5587: 5581: 5560: 5515: 5509: 5506: 5504: 5503: 5498: 5493: 5492: 5486: 5484: 5479: 5469: 5467: 5466: 5461: 5459: 5458: 5457: 5448: 5440: 5438: 5433: 5423: 5421: 5420: 5415: 5413: 5412: 5406: 5404: 5399: 5389: 5387: 5386: 5381: 5379: 5378: 5372: 5370: 5369: 5364: 5351: 5349: 5344: 5342: 5337: 5335: 5330: 5328: 5323: 5321: 5316: 5312: 5311: 5309: 5303: 5301: 5296: 5294: 5289: 5287: 5274: 5273: 5271: 5270: 5265: 5251: 5246: 5238: 5214: 5202: 5197:electronic flash 5194: 5192: 5168: 5160: 5152: 5140: 5138: 5137: 5132: 5130: 5124: 5098: 5097: 5074:electronic flash 5064: 5043: 5041: 5025: 5014: 5011: 5000: 4972: 4957: 4955: 4954: 4949: 4947: 4946: 4928: 4927: 4904: 4902: 4901: 4898: 4895: 4888: 4886: 4885: 4880: 4872: 4870: 4863: 4862: 4852: 4851: 4843: 4842: 4841: 4830: 4820: 4818: 4817: 4812: 4810: 4809: 4797: 4795: 4784: 4783: 4775: 4774: 4773: 4762: 4752: 4750: 4749: 4744: 4736: 4734: 4727: 4726: 4716: 4715: 4707: 4706: 4705: 4694: 4684: 4682: 4681: 4676: 4668: 4662: 4649: 4648: 4638: 4637: 4618: 4610: 4608: 4603: 4601: 4596: 4594: 4589: 4587: 4582: 4580: 4575: 4573: 4568: 4566: 4561: 4559: 4554: 4552: 4547: 4545: 4540: 4538: 4533: 4531: 4530: 4525: 4523: 4522: 4516: 4514: 4509: 4499: 4497: 4488: 4468: 4460: 4457: 4446: 4399: 4384: 4382: 4381: 4376: 4368: 4366: 4365: 4356: 4343: 4342: 4332: 4320: 4316: 4312: 4310: 4301: 4297: 4294: 4287: 4285: 4259: 4253: 4238: 4224: 4218: 4215: 4209: 4205: 4199: 4195: 4189: 4166: 4160: 4152: 4146: 4143: 4137: 4114: 4108: 4101: 4095: 4076: 4046:Flash comparison 3844: 3827: 3825: 3824: 3819: 3817: 3812: 3794: 3774: 3763: 3752: 3741: 3725: 3714: 3703: 3692: 3676: 3665: 3654: 3643: 3627: 3616: 3605: 3594: 3537: 3525: 3509: 3499: 3483: 3481: 3476: 3474: 3457: 3420: 3415: 3411: 3404: 3348: 3346: 3339: 3284: 3280: 3278: 3273: 3271: 3264: 3210: 3208: 3201: 3147: 3145: 3138: 3047: 3036: 2985: 2983: 2976: 2921: 2917: 2915: 2910: 2908: 2901: 2847: 2845: 2838: 2784: 2782: 2775: 2684: 2673: 2664: 2661: 2637: 2633: 2625: 2622: 2615: 2578: 2567: 2556: 2545: 2534: 2516: 2515:M SYNC, ISO 100) 2505: 2501: 2496: 2493: 2482: 2479: 2472: 2461: 2456: 2453: 2446: 2443: 2436: 2432: 2429: 2413: 2409: 2389: 2385: 2381: 2377: 2374: 2367: 2335: 2332: 2325: 2322: 2288: 2285: 2271: 2267: 2255: 2231: 2229: 2228: 2223: 2221: 2220: 2196: 2194: 2193: 2188: 2172: 2170: 2169: 2164: 2151: 2129: 2128: 2105: 1909: 1908:WITH FILTER LOSS 1900: 1885: 1883: 1882: 1877: 1875: 1870: 1857: 1855: 1854: 1849: 1847: 1846: 1818: 1816: 1815: 1810: 1794: 1792: 1791: 1786: 1776: 1748: 1746: 1745: 1736: 1687: 1396: 1389: 1380: 1376: 1347: 1345: 1336: 1332: 1313: 1143: 1134: 1086: 1084: 1083: 1078: 1076: 1071: 1062: 1059: 1044: 1042: 1041: 1036: 1018: 1016: 1015: 1010: 1000: 982: 957: 952: 939: 921: 886: 884: 883: 878: 876: 871: 858: 855: 840: 838: 837: 832: 818: 816: 815: 810: 792: 790: 789: 784: 774: 756: 731: 729: 724: 719: 714: 701: 683: 575: 568: 560: 553: 535:/imaging sensor. 450: 430: 428: 421: 419: 410: 408: 390: 388: 380: 378: 368:28 (m) / 92 (ft) 365: 363: 350: 348: 343: 341: 329: 327: 322: 320: 316: 312: 310: 306: 302: 300: 273: 254: 250: 246: 230: 209: 180: 173: 152:Units of measure 69: 67: 62: 60: 55: 53: 48: 46: 41: 39: 7846: 7845: 7841: 7840: 7839: 7837: 7836: 7835: 7811: 7810: 7809: 7804: 7774: 7731: 7678: 7669:Push processing 7590: 7583: 7577:RGB color model 7526: 7432: 7316: 7228: 7194:Diagonal method 7180: 6920: 6824:Photojournalism 6687: 6519:Black-and-white 6487: 6466:Slide projector 6461:Movie projector 6340:available films 6209: 6204: 6171:Wayback Machine 6115: 6094: 6092:Further reading 6089: 6078: 6074: 6069: 6065: 6053: 6049: 6032: 6028: 6020: 6016: 6008: 6001: 5993: 5989: 5973: 5972: 5968: 5954: 5947: 5936: 5932: 5927: 5913: 5887: 5883: 5878: 5876: 5866: 5864: 5848: 5844: 5839: 5837: 5835: 5833: 5831: 5829: 5827: 5825: 5823: 5821: 5802: 5793: 5788: 5771: 5769: 5767: 5765: 5763: 5747: 5745: 5743: 5727: 5720: 5713: 5691: 5687: 5677: 5670: 5660: 5656: 5652: 5647: 5624: 5617: 5616: 5614: 5611: 5610: 5608: 5604: 5588: 5584: 5553: 5546:folding cameras 5516: 5512: 5485: 5478: 5477: 5475: 5472: 5471: 5446: 5439: 5432: 5431: 5429: 5426: 5425: 5405: 5398: 5397: 5395: 5392: 5391: 5371: 5363: 5359: 5358: 5356: 5353: 5352: 5347: 5346: 5340: 5339: 5333: 5332: 5326: 5325: 5319: 5318: 5307: 5306: 5305: 5299: 5298: 5292: 5291: 5285: 5284: 5242: 5237: 5232: 5229: 5228: 5227: 5221: 5213:328 lux⋅seconds 5212: 5201:270 lux⋅seconds 5200: 5190: 5189: 5183: 5164: 5156: 5153:is guide number 5148: 5099: 5096: 5085: 5082: 5081: 5078: 5071: 5060: = 5053: 5047: 5039: 5038: 5029: 5023: 5018: 5010: 5006: 4996: 4970: 4965: 4942: 4938: 4923: 4919: 4917: 4914: 4913: 4907: 4906: 4899: 4896: 4893: 4892: 4890: 4858: 4854: 4853: 4847: 4837: 4833: 4832: 4831: 4829: 4827: 4824: 4823: 4821: 4805: 4801: 4785: 4779: 4769: 4765: 4764: 4763: 4761: 4759: 4756: 4755: 4753: 4722: 4718: 4717: 4711: 4701: 4697: 4696: 4695: 4693: 4691: 4688: 4687: 4685: 4644: 4640: 4639: 4636: 4634: 4631: 4630: 4614: 4606: 4605: 4599: 4598: 4592: 4591: 4585: 4584: 4578: 4577: 4571: 4570: 4564: 4563: 4557: 4556: 4550: 4549: 4543: 4542: 4536: 4535: 4534:series include 4515: 4508: 4507: 4505: 4502: 4501: 4495: 4494: 4484: 4464: 4456: 4452: 4442: 4438:Wayback Machine 4431:Wayback Machine 4397: 4392: 4361: 4357: 4338: 4334: 4333: 4331: 4329: 4326: 4325: 4322: 4318: 4315:164 lux⋅seconds 4314: 4308: 4307: 4300:328 lux⋅seconds 4299: 4293: 4289: 4283: 4282: 4279:Wayback Machine 4264: 4260: 4256: 4236: 4225: 4221: 4216: 4212: 4206: 4202: 4196: 4192: 4167: 4163: 4153: 4149: 4144: 4140: 4122:Holgon MF Flash 4115: 4111: 4102: 4098: 4077: 4073: 4069: 4032: 4004: 3993: 3967: 3956: 3927: 3916: 3914:Luminous energy 3879: 3868: 3860: 3838: 3811: 3809: 3806: 3805: 3792: 3770: 3759: 3748: 3737: 3721: 3710: 3699: 3688: 3672: 3661: 3650: 3639: 3623: 3612: 3601: 3590: 3580: 3578: 3571: 3569: 3562: 3560: 3553: 3551: 3544: 3532: 3530: 3528: 3507: 3495: 3493: 3491: 3487: 3479: 3478: 3472: 3471: 3455: 3436: 3408: 3403: 3399: 3344: 3343: 3338: 3276: 3275: 3269: 3268: 3263: 3206: 3205: 3200: 3143: 3142: 3137: 3045: 3043: 3041: 3039: 2981: 2980: 2975: 2913: 2912: 2906: 2905: 2900: 2843: 2842: 2837: 2780: 2779: 2774: 2682: 2680: 2678: 2676: 2660: 2656: 2644: 2635: 2631: 2621: 2617: 2613: 2588: 2577: 2566: 2555: 2544: 2533: 2523: 2514: 2512: 2510: 2508: 2499: 2492: 2488: 2478: 2474: 2470: 2459: 2452: 2448: 2442: 2438: 2434: 2428: 2424: 2411: 2407: 2400:flash blindness 2379: 2373: 2369: 2365: 2355:Shutter speeds 2353: 2351:With flashbulbs 2331: 2327: 2321: 2317: 2296: 2284: 2280: 2278: 2269: 2265: 2253: 2238: 2216: 2212: 2210: 2207: 2206: 2204: 2182: 2179: 2178: 2124: 2120: 2088: 2085: 2084: 2058: 2045: 2034: 2021: 2000: 1989: 1968: 1955: 1944: 1928: 1916: 1907: 1905: 1903: 1869: 1867: 1864: 1863: 1842: 1838: 1836: 1833: 1832: 1804: 1801: 1800: 1741: 1737: 1735: 1724: 1721: 1720: 1695: 1402:ISO sensitivity 1392: 1343: 1342: 1341:. When shot at 1321: 1201: 1192: 1185: 1178: 1171: 1164: 1157: 1150: 1141: 1139: 1137: 1097: 1070: 1068: 1065: 1064: 1058: 1054: 1030: 1027: 1026: 951: 907: 904: 903: 870: 868: 865: 864: 854: 850: 826: 823: 822: 804: 801: 800: 725: 720: 715: 713: 669: 666: 665: 651: 573: 569: 566: 562: 559: 555: 552: 548: 448: 437: 426: 425: 417: 416: 406: 405: 398: 386: 385: 376: 375: 361: 360: 357: 346: 345: 344:(GN 48 ÷ 6 m = 339: 338: 325: 324: 318: 317: 314: 308: 307: 304: 298: 297: 286: 268: 244: 204: 194:unit of measure 175: 169: 154: 149: 137:digital cameras 122:luminous energy 65: 64: 58: 57: 51: 50: 44: 43: 37: 36: 17: 12: 11: 5: 7844: 7834: 7833: 7828: 7823: 7806: 7805: 7803: 7802: 7791: 7779: 7776: 7775: 7773: 7772: 7767: 7762: 7757: 7756: 7755: 7750: 7739: 7737: 7733: 7732: 7730: 7729: 7728: 7727: 7722: 7717: 7712: 7702: 7697: 7692: 7686: 7684: 7680: 7679: 7677: 7676: 7671: 7666: 7661: 7656: 7651: 7646: 7641: 7636: 7631: 7626: 7621: 7616: 7611: 7606: 7601: 7595: 7593: 7585: 7584: 7582: 7581: 7580: 7579: 7574: 7569: 7564: 7554: 7549: 7548: 7547: 7536: 7534: 7528: 7527: 7525: 7524: 7519: 7514: 7513: 7512: 7507: 7502: 7497: 7487: 7482: 7477: 7472: 7471: 7470: 7465: 7460: 7459: 7458: 7446:Digital camera 7442: 7440: 7434: 7433: 7431: 7430: 7425: 7420: 7415: 7410: 7405: 7400: 7395: 7390: 7385: 7380: 7375: 7370: 7365: 7360: 7355: 7350: 7345: 7340: 7335: 7330: 7324: 7322: 7318: 7317: 7315: 7314: 7309: 7304: 7299: 7294: 7289: 7284: 7279: 7274: 7272:Camera obscura 7269: 7264: 7259: 7254: 7249: 7244: 7238: 7236: 7230: 7229: 7227: 7226: 7221: 7216: 7214:Rule of thirds 7211: 7206: 7201: 7196: 7190: 7188: 7182: 7181: 7179: 7178: 7173: 7168: 7163: 7158: 7153: 7152: 7151: 7141: 7136: 7135: 7134: 7124: 7119: 7114: 7109: 7104: 7099: 7094: 7089: 7084: 7079: 7074: 7069: 7064: 7059: 7054: 7049: 7044: 7039: 7034: 7029: 7024: 7019: 7014: 7009: 7004: 6999: 6994: 6989: 6984: 6982:Harris shutter 6979: 6977:Hand-colouring 6974: 6969: 6964: 6959: 6954: 6949: 6944: 6939: 6934: 6928: 6926: 6922: 6921: 6919: 6918: 6913: 6908: 6903: 6898: 6893: 6888: 6883: 6878: 6873: 6868: 6863: 6862: 6861: 6851: 6846: 6841: 6836: 6831: 6826: 6821: 6816: 6811: 6806: 6801: 6796: 6791: 6786: 6781: 6776: 6771: 6766: 6761: 6756: 6751: 6746: 6741: 6736: 6731: 6726: 6721: 6716: 6711: 6706: 6701: 6695: 6693: 6689: 6688: 6686: 6685: 6680: 6675: 6670: 6665: 6663:Red-eye effect 6660: 6655: 6650: 6649: 6648: 6638: 6633: 6628: 6623: 6618: 6613: 6608: 6603: 6598: 6597: 6596: 6591: 6581: 6576: 6571: 6569:Exposure value 6566: 6561: 6556: 6554:Depth of focus 6551: 6549:Depth of field 6546: 6541: 6536: 6531: 6526: 6521: 6516: 6511: 6506: 6501: 6495: 6493: 6489: 6488: 6486: 6485: 6480: 6479: 6478: 6468: 6463: 6458: 6453: 6448: 6447: 6446: 6441: 6436: 6431: 6426: 6421: 6416: 6406: 6405: 6404: 6399: 6394: 6389: 6384: 6379: 6374: 6369: 6364: 6354: 6349: 6348: 6347: 6342: 6337: 6332: 6327: 6322: 6312: 6307: 6306: 6305: 6300: 6290: 6289: 6288: 6283: 6278: 6273: 6268: 6263: 6258: 6253: 6248: 6243: 6238: 6233: 6228: 6217: 6215: 6211: 6210: 6203: 6202: 6195: 6188: 6180: 6174: 6173: 6156: 6146: 6136: 6126: 6123:Conley cameras 6114: 6113:External links 6111: 6110: 6109: 6093: 6090: 6088: 6087: 6072: 6063: 6047: 6026: 6014: 5999: 5987: 5966: 5945: 5938:Flashbulbs.com 5930: 5925: 5902: 5881: 5872: 5860: 5842: 5817: 5791: 5783: 5759: 5739: 5718: 5711: 5685: 5678:Scantips.com: 5668: 5653: 5651: 5648: 5646: 5645: 5630: 5621: 5602: 5582: 5526:"Bulb" setting 5510: 5496: 5491: 5482: 5454: 5451: 5445: 5436: 5411: 5402: 5377: 5367: 5362: 5263: 5260: 5257: 5254: 5249: 5245: 5241: 5236: 5171: 5170: 5162: 5154: 5146: 5142: 5141: 5127: 5123: 5120: 5117: 5114: 5111: 5108: 5105: 5102: 5095: 5092: 5089: 5051: 5028: 5027: 5021: 5016: 5008: 4994: 4968: 4963: 4959: 4958: 4945: 4941: 4937: 4934: 4931: 4926: 4922: 4878: 4875: 4869: 4866: 4861: 4857: 4850: 4846: 4840: 4836: 4822: 4808: 4804: 4800: 4794: 4791: 4788: 4782: 4778: 4772: 4768: 4754: 4742: 4739: 4733: 4730: 4725: 4721: 4714: 4710: 4704: 4700: 4686: 4674: 4671: 4665: 4661: 4658: 4655: 4652: 4647: 4643: 4629: 4628: 4624: 4623: 4612: 4521: 4512: 4482: 4462: 4454: 4440: 4395: 4390: 4386: 4385: 4374: 4371: 4364: 4360: 4355: 4352: 4349: 4346: 4341: 4337: 4319:82 lux⋅seconds 4291: 4254: 4219: 4210: 4200: 4198:horizontally). 4190: 4178:along the path 4161: 4147: 4138: 4109: 4096: 4070: 4068: 4065: 4064: 4063: 4058: 4053: 4048: 4043: 4041:Exposure value 4038: 4031: 4028: 4027: 4026: 4025:of that light. 4011: 4005: 4002: 3994: 3989: 3987: 3977: 3968: 3965: 3957: 3952: 3950: 3936: 3928: 3925: 3917: 3912: 3910: 3896: 3888: 3877: 3869: 3863: 3859: 3856: 3815: 3780: 3779: 3768: 3757: 3746: 3735: 3731: 3730: 3719: 3708: 3697: 3686: 3682: 3681: 3670: 3659: 3648: 3637: 3633: 3632: 3621: 3610: 3599: 3588: 3584: 3583: 3574: 3565: 3556: 3547: 3539: 3538: 3512:Prior to GE's 3435: 3432: 3430:relationship. 3401: 3395: 3394: 3391: 3388: 3385: 3382: 3379: 3376: 3373: 3370: 3367: 3364: 3361: 3358: 3355: 3352: 3349: 3336: 3332: 3331: 3328: 3325: 3322: 3319: 3316: 3313: 3310: 3307: 3304: 3301: 3298: 3295: 3292: 3289: 3286: 3261: 3257: 3256: 3253: 3250: 3247: 3244: 3241: 3238: 3235: 3232: 3229: 3226: 3223: 3220: 3217: 3214: 3211: 3198: 3194: 3193: 3190: 3187: 3184: 3181: 3178: 3175: 3172: 3169: 3166: 3163: 3160: 3157: 3154: 3151: 3148: 3135: 3131: 3130: 3125: 3120: 3115: 3110: 3105: 3100: 3095: 3090: 3085: 3080: 3075: 3070: 3065: 3060: 3055: 3049: 3048: 3032: 3031: 3028: 3025: 3022: 3019: 3016: 3013: 3010: 3007: 3004: 3001: 2998: 2995: 2992: 2989: 2986: 2973: 2969: 2968: 2965: 2962: 2959: 2956: 2953: 2950: 2947: 2944: 2941: 2938: 2935: 2932: 2929: 2926: 2923: 2898: 2894: 2893: 2890: 2887: 2884: 2881: 2878: 2875: 2872: 2869: 2866: 2863: 2860: 2857: 2854: 2851: 2848: 2835: 2831: 2830: 2827: 2824: 2821: 2818: 2815: 2812: 2809: 2806: 2803: 2800: 2797: 2794: 2791: 2788: 2785: 2772: 2768: 2767: 2762: 2757: 2752: 2747: 2742: 2737: 2732: 2727: 2722: 2717: 2712: 2707: 2702: 2697: 2692: 2686: 2685: 2658: 2643: 2640: 2619: 2607: 2606: 2603: 2600: 2597: 2594: 2591: 2583: 2582: 2575: 2571: 2564: 2560: 2553: 2549: 2542: 2538: 2531: 2526: 2518: 2517: 2490: 2476: 2467:depth of field 2450: 2440: 2426: 2371: 2352: 2349: 2329: 2319: 2295: 2292: 2282: 2276: 2237: 2234: 2219: 2215: 2202: 2199: 2198: 2186: 2174: 2173: 2162: 2159: 2156: 2150: 2147: 2144: 2141: 2138: 2135: 2132: 2127: 2123: 2119: 2116: 2113: 2110: 2104: 2101: 2098: 2095: 2092: 2072: 2071: 2068: 2063: 2060: 2056: 2051: 2050: 2047: 2043: 2039: 2036: 2032: 2027: 2026: 2023: 2019: 2015: 2012: 2006: 2005: 2002: 1998: 1994: 1991: 1987: 1982: 1981: 1978: 1973: 1970: 1966: 1961: 1960: 1957: 1953: 1949: 1946: 1942: 1937: 1936: 1931: 1924: 1919: 1911: 1910: 1904:ATTENUATION OF 1873: 1845: 1841: 1821: 1820: 1808: 1796: 1795: 1784: 1781: 1775: 1772: 1769: 1766: 1763: 1760: 1757: 1754: 1751: 1744: 1740: 1734: 1731: 1728: 1694: 1691: 1683: 1682: 1679: 1676: 1673: 1670: 1667: 1664: 1661: 1658: 1655: 1652: 1649: 1646: 1643: 1640: 1637: 1634: 1631: 1628: 1625: 1622: 1619: 1616: 1613: 1610: 1604: 1603: 1600: 1597: 1594: 1591: 1588: 1585: 1582: 1579: 1576: 1573: 1570: 1567: 1564: 1561: 1558: 1555: 1552: 1549: 1546: 1543: 1540: 1537: 1534: 1531: 1525: 1524: 1519: 1514: 1509: 1504: 1499: 1494: 1489: 1484: 1479: 1474: 1469: 1464: 1459: 1454: 1449: 1444: 1439: 1434: 1429: 1424: 1419: 1414: 1409: 1404: 1398: 1397: 1339:1438 (ft) 1320: 1317: 1309: 1308: 1305: 1302: 1299: 1296: 1293: 1290: 1287: 1283: 1282: 1279: 1276: 1273: 1270: 1267: 1264: 1261: 1257: 1256: 1253: 1250: 1247: 1244: 1241: 1238: 1235: 1231: 1230: 1227: 1224: 1221: 1218: 1215: 1212: 1209: 1205: 1204: 1195: 1188: 1181: 1174: 1167: 1160: 1153: 1145: 1144: 1096: 1093: 1074: 1056: 1047: 1046: 1034: 1024: 1020: 1019: 1008: 1005: 999: 996: 993: 990: 987: 981: 978: 975: 972: 969: 966: 963: 960: 955: 950: 947: 944: 938: 935: 932: 929: 926: 920: 917: 914: 911: 874: 852: 843: 842: 830: 820: 808: 798: 794: 793: 782: 779: 773: 770: 767: 764: 761: 755: 752: 749: 746: 743: 740: 737: 734: 728: 723: 718: 712: 709: 706: 700: 697: 694: 691: 688: 682: 679: 676: 673: 650: 647: 571: 564: 557: 550: 537: 536: 521: 508:, measured in 494: 493: 484: 481: 474: 436: 433: 432: 431: 422: 397: 394: 393: 392: 382: 356: 353: 315:GN 144 (ft) ÷ 285: 282: 243:Guide number: 196:that is a two- 162:aperture ratio 153: 150: 148: 145: 106: 105: 104: 103: 15: 9: 6: 4: 3: 2: 7843: 7832: 7831:Light sources 7829: 7827: 7824: 7822: 7819: 7818: 7816: 7801: 7792: 7790: 7781: 7780: 7777: 7771: 7768: 7766: 7763: 7761: 7758: 7754: 7751: 7749: 7746: 7745: 7744: 7741: 7740: 7738: 7734: 7726: 7723: 7721: 7718: 7716: 7713: 7711: 7708: 7707: 7706: 7705:Photographers 7703: 7701: 7698: 7696: 7693: 7691: 7688: 7687: 7685: 7681: 7675: 7672: 7670: 7667: 7665: 7662: 7660: 7657: 7655: 7652: 7650: 7647: 7645: 7642: 7640: 7637: 7635: 7632: 7630: 7627: 7625: 7622: 7620: 7617: 7615: 7612: 7610: 7607: 7605: 7602: 7600: 7599:Bleach bypass 7597: 7596: 7594: 7592: 7586: 7578: 7575: 7573: 7570: 7568: 7567:primary color 7565: 7563: 7560: 7559: 7558: 7555: 7553: 7552:Reversal film 7550: 7546: 7543: 7542: 7541: 7538: 7537: 7535: 7533: 7529: 7523: 7520: 7518: 7517:Image sharing 7515: 7511: 7508: 7506: 7503: 7501: 7498: 7496: 7493: 7492: 7491: 7488: 7486: 7483: 7481: 7478: 7476: 7473: 7469: 7466: 7464: 7461: 7457: 7454: 7453: 7452: 7449: 7448: 7447: 7444: 7443: 7441: 7439: 7435: 7429: 7426: 7424: 7421: 7419: 7418:United States 7416: 7414: 7411: 7409: 7406: 7404: 7401: 7399: 7396: 7394: 7391: 7389: 7386: 7384: 7381: 7379: 7376: 7374: 7371: 7369: 7366: 7364: 7361: 7359: 7356: 7354: 7351: 7349: 7346: 7344: 7341: 7339: 7336: 7334: 7331: 7329: 7326: 7325: 7323: 7319: 7313: 7310: 7308: 7305: 7303: 7300: 7298: 7295: 7293: 7290: 7288: 7285: 7283: 7280: 7278: 7277:Daguerreotype 7275: 7273: 7270: 7268: 7265: 7263: 7260: 7258: 7255: 7253: 7250: 7248: 7245: 7243: 7240: 7239: 7237: 7235: 7231: 7225: 7222: 7220: 7217: 7215: 7212: 7210: 7207: 7205: 7202: 7200: 7197: 7195: 7192: 7191: 7189: 7187: 7183: 7177: 7174: 7172: 7169: 7167: 7164: 7162: 7159: 7157: 7154: 7150: 7147: 7146: 7145: 7142: 7140: 7137: 7133: 7130: 7129: 7128: 7125: 7123: 7122:Stopping down 7120: 7118: 7115: 7113: 7110: 7108: 7105: 7103: 7100: 7098: 7095: 7093: 7090: 7088: 7087:Rephotography 7085: 7083: 7080: 7078: 7075: 7073: 7070: 7068: 7065: 7063: 7060: 7058: 7055: 7053: 7050: 7048: 7045: 7043: 7040: 7038: 7035: 7033: 7030: 7028: 7025: 7023: 7022:Long-exposure 7020: 7018: 7015: 7013: 7010: 7008: 7005: 7003: 7000: 6998: 6995: 6993: 6990: 6988: 6985: 6983: 6980: 6978: 6975: 6973: 6970: 6968: 6965: 6963: 6960: 6958: 6955: 6953: 6950: 6948: 6945: 6943: 6940: 6938: 6935: 6933: 6930: 6929: 6927: 6923: 6917: 6914: 6912: 6909: 6907: 6904: 6902: 6899: 6897: 6894: 6892: 6889: 6887: 6884: 6882: 6879: 6877: 6874: 6872: 6869: 6867: 6864: 6860: 6857: 6856: 6855: 6852: 6850: 6847: 6845: 6842: 6840: 6837: 6835: 6832: 6830: 6827: 6825: 6822: 6820: 6817: 6815: 6812: 6810: 6807: 6805: 6802: 6800: 6797: 6795: 6792: 6790: 6787: 6785: 6782: 6780: 6777: 6775: 6772: 6770: 6767: 6765: 6762: 6760: 6757: 6755: 6752: 6750: 6747: 6745: 6742: 6740: 6737: 6735: 6732: 6730: 6727: 6725: 6722: 6720: 6717: 6715: 6714:Architectural 6712: 6710: 6707: 6705: 6702: 6700: 6697: 6696: 6694: 6690: 6684: 6681: 6679: 6676: 6674: 6673:Shutter speed 6671: 6669: 6666: 6664: 6661: 6659: 6656: 6654: 6651: 6647: 6644: 6643: 6642: 6639: 6637: 6634: 6632: 6629: 6627: 6626:Metering mode 6624: 6622: 6619: 6617: 6614: 6612: 6609: 6607: 6604: 6602: 6599: 6595: 6592: 6590: 6587: 6586: 6585: 6582: 6580: 6577: 6575: 6572: 6570: 6567: 6565: 6562: 6560: 6557: 6555: 6552: 6550: 6547: 6545: 6542: 6540: 6539:Color balance 6537: 6535: 6532: 6530: 6527: 6525: 6522: 6520: 6517: 6515: 6512: 6510: 6507: 6505: 6504:Angle of view 6502: 6500: 6497: 6496: 6494: 6490: 6484: 6481: 6477: 6474: 6473: 6472: 6469: 6467: 6464: 6462: 6459: 6457: 6454: 6452: 6451:Manufacturers 6449: 6445: 6442: 6440: 6437: 6435: 6432: 6430: 6427: 6425: 6422: 6420: 6417: 6415: 6412: 6411: 6410: 6407: 6403: 6400: 6398: 6395: 6393: 6390: 6388: 6385: 6383: 6380: 6378: 6375: 6373: 6370: 6368: 6365: 6363: 6360: 6359: 6358: 6355: 6353: 6350: 6346: 6343: 6341: 6338: 6336: 6333: 6331: 6328: 6326: 6323: 6321: 6318: 6317: 6316: 6313: 6311: 6308: 6304: 6301: 6299: 6296: 6295: 6294: 6291: 6287: 6284: 6282: 6279: 6277: 6274: 6272: 6269: 6267: 6264: 6262: 6259: 6257: 6254: 6252: 6249: 6247: 6244: 6242: 6239: 6237: 6234: 6232: 6229: 6227: 6224: 6223: 6222: 6219: 6218: 6216: 6212: 6208: 6201: 6196: 6194: 6189: 6187: 6182: 6181: 6178: 6172: 6168: 6165: 6164: 6160: 6157: 6155: 6154: 6150: 6149:Scantips.com: 6147: 6145: 6144: 6140: 6139:Scantips.com: 6137: 6135: 6134: 6130: 6127: 6125: 6124: 6120: 6117: 6116: 6108: 6107:9780817439569 6104: 6100: 6096: 6095: 6083: 6076: 6067: 6058: 6051: 6043: 6039: 6038: 6030: 6023: 6018: 6011: 6006: 6004: 5996: 5991: 5983: 5977: 5969: 5963: 5959: 5952: 5950: 5943: 5939: 5934: 5922: 5918: 5910: 5906: 5900:) as follows: 5899: 5895: 5891: 5885: 5875: 5870: 5863: 5862:Blitzleistung 5857: 5853: 5846: 5820: 5814: 5810: 5806: 5800: 5798: 5796: 5786: 5780: 5776: 5762: 5756: 5752: 5742: 5736: 5732: 5725: 5723: 5714: 5708: 5704: 5699: 5698: 5689: 5683: 5682: 5675: 5673: 5666: 5665: 5658: 5654: 5628: 5619: 5606: 5600: 5596: 5592: 5586: 5580: 5578: 5574: 5570: 5565: 5558: 5551: 5547: 5543: 5539: 5535: 5531: 5527: 5520: 5514: 5508: 5489: 5480: 5452: 5449: 5443: 5434: 5409: 5400: 5375: 5365: 5281: 5276: 5255: 5252: 5247: 5243: 5239: 5225: 5220: 5216: 5210: 5207:equals 0.981 5206: 5198: 5186: 5182: 5180: 5176: 5167: 5163: 5159: 5155: 5151: 5147: 5144: 5143: 5125: 5121: 5118: 5115: 5112: 5109: 5106: 5103: 5100: 5093: 5090: 5087: 5080: 5079: 5077: 5075: 5070: 5066: 5063: 5059: 5055: 5045: 5032: 5024: 5017: 5004: 4999: 4995: 4992: 4988: 4984: 4980: 4976: 4971: 4964: 4961: 4960: 4943: 4939: 4935: 4932: 4929: 4924: 4920: 4912: 4911: 4910: 4876: 4873: 4867: 4864: 4859: 4855: 4848: 4844: 4838: 4834: 4806: 4802: 4798: 4792: 4789: 4786: 4780: 4776: 4770: 4766: 4740: 4737: 4731: 4728: 4723: 4719: 4712: 4708: 4702: 4698: 4672: 4669: 4663: 4659: 4656: 4653: 4650: 4645: 4641: 4627: 4622: 4617: 4613: 4519: 4510: 4492: 4487: 4483: 4480: 4476: 4472: 4467: 4463: 4450: 4445: 4441: 4439: 4435: 4432: 4428: 4425: 4421: 4420: 4415: 4411: 4407: 4403: 4398: 4391: 4388: 4387: 4372: 4369: 4362: 4358: 4353: 4350: 4347: 4344: 4339: 4335: 4324: 4323: 4305: 4280: 4276: 4273: 4269: 4268:PDF here 4263: 4258: 4250: 4246: 4245:press cameras 4242: 4237:15–22 ms 4234: 4230: 4223: 4214: 4204: 4194: 4187: 4183: 4179: 4175: 4171: 4165: 4158: 4151: 4142: 4135: 4131: 4128:and the Metz 4127: 4123: 4119: 4113: 4106: 4100: 4093: 4089: 4085: 4081: 4075: 4071: 4062: 4059: 4057: 4054: 4052: 4049: 4047: 4044: 4042: 4039: 4037: 4034: 4033: 4024: 4020: 4015: 4012: 4009: 4006: 4001: 3998: 3995: 3992: 3985: 3981: 3978: 3975: 3972: 3969: 3964: 3961: 3958: 3955: 3948: 3944: 3940: 3937: 3935: 3932: 3929: 3924: 3921: 3918: 3915: 3908: 3904: 3900: 3897: 3895: 3892: 3889: 3886: 3884: 3876: 3873: 3870: 3866: 3865:Luminous flux 3861: 3855: 3853: 3849: 3842: 3837: 3835: 3830: 3813: 3802: 3798: 3789: 3787: 3778: 3773: 3769: 3767: 3762: 3758: 3756: 3751: 3747: 3745: 3740: 3736: 3733: 3732: 3729: 3724: 3720: 3718: 3713: 3709: 3707: 3702: 3698: 3696: 3691: 3687: 3684: 3683: 3680: 3675: 3671: 3669: 3664: 3660: 3658: 3653: 3649: 3647: 3642: 3638: 3635: 3634: 3631: 3626: 3622: 3620: 3615: 3611: 3609: 3604: 3600: 3598: 3593: 3589: 3586: 3585: 3582: 3575: 3573: 3566: 3564: 3557: 3555: 3548: 3546: 3541: 3540: 3535: 3526: 3523: 3520: 3515: 3510: 3504: 3497: 3486: 3469: 3465: 3460: 3449: 3445: 3440: 3431: 3428: 3422: 3419: 3392: 3389: 3386: 3383: 3380: 3377: 3374: 3371: 3368: 3365: 3362: 3359: 3356: 3353: 3350: 3334: 3333: 3330:35.8 ft 3329: 3327:33.8 ft 3326: 3324:28.6 ft 3323: 3321:24.3 ft 3320: 3318:21.2 ft 3317: 3315:17.2 ft 3314: 3312:14.3 ft 3311: 3309:12.2 ft 3308: 3306:10.3 ft 3305: 3302: 3299: 3296: 3293: 3290: 3287: 3259: 3258: 3255:28.4 ft 3254: 3252:26.8 ft 3251: 3249:22.7 ft 3248: 3246:19.3 ft 3245: 3243:16.8 ft 3242: 3240:13.6 ft 3239: 3237:11.4 ft 3236: 3233: 3230: 3227: 3224: 3221: 3218: 3215: 3212: 3196: 3195: 3192:20.1 ft 3191: 3189:18.9 ft 3188: 3186:16.1 ft 3185: 3183:13.6 ft 3182: 3180:11.9 ft 3179: 3176: 3173: 3170: 3167: 3164: 3161: 3158: 3155: 3152: 3149: 3133: 3132: 3129: 3126: 3124: 3121: 3119: 3116: 3114: 3111: 3109: 3106: 3104: 3101: 3099: 3096: 3094: 3091: 3089: 3086: 3084: 3081: 3079: 3076: 3074: 3071: 3069: 3066: 3064: 3061: 3059: 3056: 3054: 3051: 3050: 3037: 3029: 3026: 3023: 3020: 3017: 3014: 3011: 3008: 3005: 3002: 2999: 2996: 2993: 2990: 2987: 2971: 2970: 2966: 2963: 2960: 2957: 2954: 2951: 2948: 2945: 2942: 2939: 2936: 2933: 2930: 2927: 2924: 2896: 2895: 2891: 2888: 2885: 2882: 2879: 2876: 2873: 2870: 2867: 2864: 2861: 2858: 2855: 2852: 2849: 2833: 2832: 2828: 2825: 2822: 2819: 2816: 2813: 2810: 2807: 2804: 2801: 2798: 2795: 2792: 2789: 2786: 2770: 2769: 2766: 2763: 2761: 2758: 2756: 2753: 2751: 2748: 2746: 2743: 2741: 2738: 2736: 2733: 2731: 2728: 2726: 2723: 2721: 2718: 2716: 2713: 2711: 2708: 2706: 2703: 2701: 2698: 2696: 2693: 2691: 2688: 2687: 2677:—METER BASED— 2674: 2671: 2667: 2654: 2649: 2639: 2632:19–20 ms 2628: 2604: 2601: 2598: 2595: 2592: 2590: 2585: 2584: 2581: 2572: 2570: 2561: 2559: 2550: 2548: 2539: 2537: 2527: 2525: 2520: 2519: 2506: 2503: 2486: 2485:140 (ft) 2468: 2463: 2421: 2417: 2403: 2401: 2397: 2393: 2392:320 (ft) 2362: 2358: 2348: 2346: 2345: 2338: 2313: 2311: 2310: 2305: 2301: 2275: 2262: 2250: 2242: 2233: 2217: 2213: 2184: 2176: 2175: 2160: 2157: 2154: 2148: 2145: 2142: 2139: 2136: 2133: 2130: 2125: 2121: 2117: 2114: 2111: 2108: 2102: 2099: 2096: 2093: 2090: 2083: 2082: 2081: 2078: 2069: 2067: 2064: 2061: 2059: 2053: 2052: 2048: 2046: 2040: 2037: 2035: 2029: 2028: 2024: 2022: 2016: 2013: 2011: 2008: 2007: 2003: 2001: 1995: 1992: 1990: 1984: 1983: 1979: 1977: 1974: 1971: 1969: 1963: 1962: 1958: 1956: 1950: 1947: 1945: 1939: 1938: 1935: 1932: 1930: 1925: 1923: 1920: 1918: 1913: 1912: 1906:GUIDE NUMBERS 1901: 1898: 1895: 1893: 1889: 1871: 1862:of that (the 1861: 1843: 1839: 1830: 1826: 1806: 1798: 1797: 1782: 1779: 1773: 1770: 1767: 1764: 1761: 1758: 1755: 1752: 1749: 1742: 1738: 1732: 1729: 1726: 1719: 1718: 1717: 1714: 1712: 1708: 1703: 1700: 1690: 1680: 1677: 1674: 1671: 1668: 1665: 1662: 1659: 1656: 1653: 1650: 1647: 1644: 1641: 1638: 1635: 1632: 1629: 1626: 1623: 1620: 1617: 1614: 1611: 1609: 1606: 1605: 1601: 1598: 1595: 1592: 1589: 1586: 1583: 1580: 1577: 1574: 1571: 1568: 1565: 1562: 1559: 1556: 1553: 1550: 1547: 1544: 1541: 1538: 1535: 1532: 1530: 1527: 1526: 1523: 1520: 1518: 1515: 1513: 1510: 1508: 1505: 1503: 1500: 1498: 1495: 1493: 1490: 1488: 1485: 1483: 1480: 1478: 1475: 1473: 1470: 1468: 1465: 1463: 1460: 1458: 1455: 1453: 1450: 1448: 1445: 1443: 1440: 1438: 1435: 1433: 1430: 1428: 1425: 1423: 1420: 1418: 1415: 1413: 1410: 1408: 1405: 1403: 1400: 1399: 1395: 1390: 1387: 1384: 1371: 1366: 1363: 1359: 1355: 1349: 1340: 1325: 1316: 1306: 1303: 1300: 1297: 1294: 1291: 1288: 1285: 1284: 1280: 1277: 1274: 1271: 1268: 1265: 1262: 1259: 1258: 1254: 1251: 1248: 1245: 1242: 1239: 1236: 1233: 1232: 1228: 1225: 1222: 1219: 1216: 1213: 1210: 1207: 1206: 1203: 1200: 1196: 1194: 1189: 1187: 1182: 1180: 1175: 1173: 1168: 1166: 1161: 1159: 1154: 1152: 1147: 1146: 1135: 1132: 1129: 1127: 1124:, reflector, 1123: 1117: 1115: 1112:often—though 1109: 1105: 1103: 1092: 1090: 1072: 1052: 1032: 1025: 1022: 1021: 1006: 1003: 997: 994: 991: 988: 985: 979: 976: 973: 970: 967: 964: 961: 958: 953: 948: 945: 942: 936: 933: 930: 927: 924: 918: 915: 912: 909: 902: 901: 900: 896: 894: 890: 872: 863:of that (the 862: 848: 828: 821: 806: 799: 796: 795: 780: 777: 771: 768: 765: 762: 759: 753: 750: 747: 744: 741: 738: 735: 732: 726: 721: 716: 710: 707: 704: 698: 695: 692: 689: 686: 680: 677: 674: 671: 664: 663: 662: 659: 657: 646: 644: 643: 636: 633: 628: 626: 625: 620: 619: 613: 609: 605: 601: 597: 592: 590: 589: 583: 581: 580: 544: 542: 534: 530: 526: 522: 519: 515: 511: 507: 503: 499: 498: 497: 491: 490: 485: 482: 479: 475: 472: 471: 466: 465:luminous flux 462: 461:lumen⋅seconds 458: 457: 456: 446: 441: 423: 414: 413: 412: 403: 383: 373: 372: 371: 369: 352: 336: 331: 305:(GN 44 (m) ÷ 295: 290: 281: 279: 274: 271: 265: 261: 256: 255: 240: 236: 228: 224: 220: 216: 211: 207: 202: 199: 195: 191: 187: 178: 172: 167: 163: 158: 144: 140: 138: 134: 129: 127: 123: 118: 116: 112: 101: 100: 99: 98: 97: 94: 92: 91:f‑stop 88: 84: 80: 77: 74:When setting 34: 30: 26: 21: 7765:Polaroid art 7659:K-14 process 7654:Instant film 7649:Gum printing 7604:C-41 process 7589:Photographic 7490:Image sensor 7485:Film scanner 7139:Sun printing 7072:Print toning 6859:space selfie 6829:Pictorialism 6759:Ethnographic 6739:Conservation 6611:Guide number 6610: 6606:Focal length 6162: 6159:Sekonic.com: 6152: 6142: 6132: 6121: 6098: 6081: 6075: 6066: 6056: 6050: 6036: 6029: 6021: 6017: 6009: 5994: 5990: 5957: 5942:"Flash info" 5933: 5920: 5908: 5904: 5894:VS 510P 5893: 5890:single-prime 5884: 5874:Flash output 5873: 5868: 5861: 5851: 5845: 5819:Guide Number 5818: 5808: 5804: 5785:Guide Number 5784: 5774: 5761:Guide Number 5760: 5750: 5741:Flash output 5740: 5730: 5696: 5688: 5679: 5662: 5657: 5605: 5598: 5594: 5590: 5585: 5576: 5572: 5568: 5561: 5555: 5549: 5542:flash powder 5529: 5513: 5279: 5277: 5223: 5218: 5217: 5196: 5195:), a proper 5187: 5184: 5181:) for more. 5174: 5172: 5165: 5157: 5149: 5073: 5068: 5067: 5061: 5057: 5049: 5033: 5030: 5019: 5015:of a second) 5002: 4997: 4990: 4986: 4982: 4966: 4908: 4625: 4620: 4615: 4490: 4485: 4478: 4474: 4470: 4465: 4461:of a second) 4448: 4443: 4418: 4413: 4409: 4393: 4261: 4257: 4228: 4222: 4213: 4203: 4193: 4181: 4177: 4169: 4164: 4156: 4150: 4141: 4133: 4129: 4125: 4121: 4112: 4105:watt⋅seconds 4099: 4091: 4083: 4079: 4074: 4022: 4018: 4013: 4007: 3999: 3996: 3983: 3979: 3970: 3962: 3959: 3946: 3942: 3938: 3934:Lumen⋅second 3930: 3922: 3919: 3906: 3898: 3890: 3881: 3880:(pronounced 3874: 3871: 3851: 3847: 3845: 3840: 3833: 3831: 3800: 3796: 3793:No. 11 3790: 3785: 3783: 3776: 3771: 3765: 3760: 3754: 3749: 3743: 3738: 3727: 3722: 3716: 3711: 3705: 3700: 3694: 3689: 3678: 3673: 3667: 3662: 3656: 3651: 3645: 3640: 3629: 3624: 3618: 3613: 3607: 3602: 3596: 3591: 3576: 3567: 3558: 3549: 3542: 3533: 3518: 3513: 3511: 3508:No. 5. 3500: 3490:Then simply: 3489: 3464:flash powder 3461: 3456:No. 5. 3453: 3444:flash powder 3426: 3423: 3409: 3398: 3303:8.6 ft 3300:7.2 ft 3297:5.6 ft 3294:4.7 ft 3291:3.7 ft 3288:3.0 ft 3234:9.7 ft 3231:8.2 ft 3228:6.8 ft 3225:5.7 ft 3222:4.4 ft 3219:3.7 ft 3216:3.0 ft 3213:2.4 ft 3177:9.6 ft 3174:8.0 ft 3171:6.8 ft 3168:5.8 ft 3165:4.8 ft 3162:4.0 ft 3159:3.1 ft 3156:2.6 ft 3153:2.1 ft 3150:1.7 ft 3127: 3122: 3117: 3112: 3107: 3102: 3097: 3092: 3087: 3082: 3077: 3072: 3067: 3062: 3057: 3052: 3040:—FOOT BASED— 2764: 2759: 2754: 2749: 2744: 2739: 2734: 2729: 2724: 2719: 2714: 2709: 2704: 2699: 2694: 2689: 2668: 2645: 2629: 2614:No. 11 2610: 2586: 2573: 2562: 2551: 2540: 2529: 2521: 2500:No. 11 2484: 2471:No. 11 2464: 2460:No. 11 2435:No. 11 2416:leaf shutter 2412:No. 11 2408:No. 11 2404: 2396:baby boomers 2383: 2380:No. 11 2366:No. 11 2356: 2354: 2342: 2339: 2314: 2307: 2297: 2273: 2270:No. 11 2266:No. 11 2200: 2079: 2075: 2065: 2054: 2041: 2030: 2017: 2009: 1996: 1985: 1975: 1964: 1951: 1940: 1933: 1926: 1921: 1914: 1896: 1891: 1887: 1824: 1822: 1715: 1704: 1696: 1686: 1607: 1528: 1521: 1516: 1511: 1506: 1501: 1496: 1491: 1486: 1481: 1476: 1471: 1466: 1461: 1456: 1451: 1446: 1441: 1436: 1431: 1426: 1421: 1416: 1411: 1406: 1401: 1393: 1374: 1369: 1367: 1364: 1360: 1356: 1352: 1331:438 (m) 1330: 1328: 1312: 1208:105 mm 1197: 1190: 1183: 1179:430EX III-RT 1176: 1169: 1162: 1155: 1148: 1130: 1126:Fresnel lens 1118: 1113: 1110: 1106: 1098: 1088: 1050: 1048: 897: 892: 888: 846: 844: 660: 652: 640: 637: 632:flash device 631: 629: 622: 616: 611: 603: 593: 586: 584: 577: 545: 540: 538: 529:lens filters 524: 513: 501: 495: 487: 468: 454: 449:lux⋅seconds) 444: 401: 399: 367: 358: 334: 332: 313:= 11 m, and 293: 291: 287: 277: 275: 269: 263: 260:length-based 259: 257: 242: 238: 234: 222: 218: 212: 205: 189: 183: 176: 170: 165: 161: 141: 130: 119: 114: 110: 107: 95: 86: 83:guide number 82: 73: 32: 28: 25:guide number 24: 7770:Stereoscopy 7634:E-6 process 7629:Dye coupler 7562:color space 7475:Digiscoping 7468:camera back 7383:Philippines 7312:Visual arts 7302:Glass plate 7287:Heliography 7186:Composition 7161:Ultraviolet 7117:Stereoscopy 7112:Slow motion 7097:Scanography 7012:Kite aerial 6952:Contre-jour 6844:Post-mortem 6834:Pornography 6814:Neues Sehen 6749:Documentary 6683:Zone System 6658:Reciprocity 6584:Film format 6514:Backscatter 6492:Terminology 6362:beauty dish 6261:rangefinder 6226:light-field 6207:Photography 5534:view camera 5205:candlepower 4975:illuminance 4402:illuminance 4188:) for more. 4014:Definition: 3980:Definition: 3954:Illuminance 3939:Definition: 3899:Definition: 3579:in ordinary 3570:in ordinary 2636:No. 6 2589:number (ft) 2420:M sync 2254:No. 5 1860:square root 1286:28 mm 1260:35 mm 1234:50 mm 861:square root 624:Light meter 608:lux⋅seconds 600:illuminance 596:reflectance 506:illuminance 478:solid angle 280:by 0.3048. 253:98 ft. 227:foot symbol 7815:Categories 7760:Lomography 7591:processing 7540:Print film 7456:comparison 7423:Uzbekistan 7373:Luxembourg 7333:Bangladesh 7282:Dufaycolor 7262:Box camera 7219:Simplicity 7176:Zoom burst 7171:Xerography 7166:Vignetting 7156:Time-lapse 7144:Tilt–shift 7037:Mordançage 7027:Luminogram 6992:Holography 6987:High-speed 6967:Fill flash 6947:Burst mode 6925:Techniques 6906:Vernacular 6901:Underwater 6896:Toy camera 6876:Still life 6804:Monochrome 6794:High-speed 6744:Cloudscape 6734:Conceptual 6636:Photograph 6621:Lens flare 6601:Film speed 6483:Zone plate 6429:wide-angle 6414:long-focus 5838:20°C/68°F) 5650:References 5538:flash-lamp 4241:Hasselblad 4208:equations. 4084:speedlight 4080:Speedlight 4019:brightness 4010:Lux⋅second 3984:brightness 3577:Large bulb 3568:Small bulb 3559:Large bulb 3550:Small bulb 3448:flash-lamp 2361:flashbulbs 1122:flash tube 1114:not always 606:that have 518:color gels 133:flashbulbs 126:film speed 76:photoflash 7710:Norwegian 7674:Stop bath 7619:Developer 7247:Ambrotype 7209:Lead room 7132:Slit-scan 7067:Photogram 7062:Panoramic 6972:Fireworks 6957:Cyanotype 6799:Landscape 6444:telephoto 6392:reflector 6387:monolight 6382:lens hood 6367:cucoloris 6303:safelight 6214:Equipment 5976:cite book 5557:duration. 5259:% 5113:× 5012: th 4973:is scene 4930:⋅ 4865:⋅ 4845:⋅ 4790:⋅ 4777:⋅ 4729:⋅ 4709:⋅ 4657:⋅ 4651:⋅ 4458: th 4400:is scene 4351:⋅ 4345:⋅ 4295: th 4126:HVL-F58AM 4092:Speedlite 4061:Flashtube 3581:reflector 3572:reflector 3563:reflector 3554:reflector 3545:(in feet) 3501:In 1932, 3405: th 3340: th 3265: th 3202: th 3139: th 2977: th 2902: th 2839: th 2776: th 2662: th 2623: th 2524:speed (s) 2494: th 2480: th 2454: th 2444: th 2430: th 2375: th 2333: th 2323: th 2300:flashtube 2286: th 2118:× 1733:× 1383:4000 (ft) 1165:HVL-F58AM 1108:number). 1060: nd 949:÷ 856: th 711:× 618:Gray card 591:, below. 582:, below. 527:; namely 512:) or its 502:intensity 264:notations 225:, or the 79:exposures 7789:Category 7495:CMOS APS 7393:Slovenia 7321:Regional 7267:Calotype 7204:Headroom 7082:Redscale 6997:Infrared 6942:Brenizer 6916:Wildlife 6839:Portrait 6784:Forensic 6774:Fine-art 6709:Aircraft 6699:Abstract 6579:F-number 6559:Exposure 6534:Clipping 6509:Aperture 6377:hot shoe 6298:enlarger 6293:Darkroom 6167:Archived 6070:Page 127 5579:(1955). 5329:/11.3137 5179:PDF here 4602:/22.6274 4588:/11.3137 4434:Archived 4427:Archived 4275:Archived 4186:PDF here 4168:Whereas 4118:hot shoe 4088:hot shoe 4030:See also 4023:duration 3943:quantity 3858:Glossary 3561:in metal 3552:in metal 3543:Distance 3536:, p. 317 3030:12.20 m 3027:11.56 m 2967:10.87 m 2964:10.30 m 2384:97.5 (m) 1375:1220 (m) 1172:YN-568EX 612:arriving 531:and the 514:duration 492:, below. 470:Glossary 278:multiply 166:distance 7800:Outline 7736:Related 7428:Vietnam 7413:Ukraine 7348:Denmark 7328:Albania 7307:Tintype 7234:History 7199:Framing 7092:Rollout 7057:Panning 7007:Kirlian 6911:Wedding 6789:Glamour 6769:Fashion 6754:Eclipse 6724:Banquet 6646:Albumen 6456:Monopod 6434:fisheye 6402:softbox 6251:pinhole 6241:instant 6231:digital 6010:Minicam 5643:series. 5350:/5.6569 5343:/6.3496 5313: 5224:outdoor 5209:candela 5145:…where, 4991:111,000 4962:…where, 4903:⁠ 4891:⁠ 4574:/5.6569 4560:/2.8284 4546:/1.4142 4539:/1.1892 4419:111,000 4389:…where, 4252:speeds. 4249:Graflex 3997:Symbol: 3960:Symbol: 3920:Symbol: 3885:sub vee 3872:Symbol: 3503:Philips 3434:History 3418:72 (ft) 3416: 3412: 3281: 3260: / 3053:GN (ft) 3024:9.63 m 3021:8.35 m 3018:7.23 m 3015:5.78 m 3012:4.82 m 3009:4.17 m 3006:3.53 m 3003:2.89 m 3000:2.41 m 2997:1.93 m 2994:1.61 m 2991:1.28 m 2988:1.04 m 2961:8.58 m 2958:7.44 m 2955:6.44 m 2952:5.15 m 2949:4.29 m 2946:3.72 m 2943:3.15 m 2940:2.57 m 2937:2.15 m 2934:1.72 m 2931:1.43 m 2928:1.14 m 2925:0.93 m 2918: 2892:8.63 m 2889:8.17 m 2886:6.81 m 2883:5.90 m 2880:5.11 m 2877:4.09 m 2874:3.41 m 2871:2.95 m 2868:2.50 m 2865:2.04 m 2862:1.70 m 2859:1.36 m 2856:1.14 m 2853:0.91 m 2850:0.74 m 2829:6.10 m 2826:5.78 m 2823:4.82 m 2820:4.17 m 2817:3.61 m 2814:2.89 m 2811:2.41 m 2808:2.09 m 2805:1.77 m 2802:1.45 m 2799:1.20 m 2796:0.96 m 2793:0.80 m 2790:0.64 m 2787:0.52 m 2522:Shutter 2390: 2386: 2357:used to 2177:…where 1799:…where 1522:409,600 1517:204,800 1512:102,400 1381: 1377: 1337: 1333: 1193:58 AF-2 1170:Yongnuo 435:Details 391:= 33 ft 251: 247: 231: 201:product 7798: 7787: 7720:street 7715:Polish 7408:Turkey 7403:Taiwan 7388:Serbia 7378:Norway 7353:Greece 7338:Canada 6932:Afocal 6891:Street 6871:Sports 6854:Selfie 6809:Nature 6764:Erotic 6729:Candid 6704:Aerial 6692:Genres 6594:medium 6471:Tripod 6439:swivel 6352:Filter 6330:holder 6325:format 6221:Camera 6105: 5964: 5709: 5626: 5567:their 5536:and a 5530:rubber 5487: 5470:, and 5441: 5407: 5373: 5345:, and 5317:, and 5185: 5037:sunny 5031: 4989:; and 4987:81,900 4983:40,960 4981:(e.g. 4889:(take 4604:, and 4517: 4477:, and 4416:; and 4414:81,900 4410:40,960 4408:(e.g. 4174:albedo 3947:amount 3410:22 (m) 2690:GN (m) 2152: 2106: 2070:35.4% 2062:59.5% 2049:39.7% 2038:63.0% 2025:42.0% 2014:70.7% 2004:44.5% 1993:79.4% 1980:50.0% 1972:84.1% 1959:56.1% 1948:89.1% 1934:Factor 1927:f-stop 1922:Factor 1915:f-stop 1777: 1633:0.891 1630:0.794 1627:0.707 1624:0.630 1621:0.561 1618:0.500 1615:0.445 1612:0.397 1545:0.891 1542:0.794 1539:0.707 1536:0.630 1533:0.561 1507:51,200 1502:25,600 1497:12,800 1304:53.4% 1301:60.6% 1298:55.8% 1295:51.7% 1292:53.4% 1289:50.0% 1278:60.3% 1275:68.4% 1272:65.1% 1269:67.2% 1266:62.1% 1263:71.4% 1252:72.4% 1249:80.7% 1246:76.8% 1243:72.4% 1240:72.4% 1237:85.7% 1199:Median 1186:SB-900 1023:…where 1001: 983: 940: 922: 797:…where 775: 757: 702: 684: 381:= 10 m 198:factor 81:, the 7725:women 7683:Lists 7639:Fixer 7522:Pixel 7451:D-SLR 7398:Sudan 7368:Korea 7363:Japan 7358:India 7343:China 7127:Strip 7052:Night 7032:Macro 6937:Bokeh 6881:Stock 6849:Ruins 6589:large 6419:prime 6397:snoot 6357:Flash 6335:stock 6310:Drone 6271:still 6256:press 6246:phone 6236:field 5907:from 5540:with 5203:(one 5003:0.008 4449:0.008 4247:like 4170:scene 4067:Notes 4008:Unit: 3971:Unit: 3931:Unit: 3894:Lumen 3891:Unit: 3777:(127) 3775::6.3 3764::4.5 3755:(226) 3744:(127) 3742::6.3 3728:(170) 3715::6.3 3706:(240) 3695:(170) 3679:(160) 3668:(113) 3657:(226) 3646:(160) 3630:(136) 3608:(192) 3597:(136) 3468:torch 3446:in a 2646:When 2587:Guide 2487:at a 1681:45.3 1678:32.0 1675:22.6 1672:16.0 1669:11.3 1666:8.00 1663:5.66 1660:4.00 1657:2.83 1654:2.00 1651:1.78 1648:1.59 1645:1.41 1642:1.26 1639:1.12 1636:1.00 1602:64.0 1599:45.3 1596:32.0 1593:22.6 1590:16.0 1587:11.3 1584:8.00 1581:5.66 1578:4.00 1575:2.83 1572:2.52 1569:2.24 1566:2.00 1563:1.78 1560:1.59 1557:1.41 1554:1.26 1551:1.12 1548:1.00 1229:100% 1226:100% 1223:100% 1220:100% 1217:100% 1214:100% 1211:100% 1202:value 1184:Nikon 1177:Canon 1151:angle 1149:Flash 567:.... 7748:film 7463:MILC 6962:ETTR 6819:Nude 6779:Fire 6678:Sync 6476:head 6424:zoom 6409:Lens 6372:gobo 6320:base 6315:Film 6286:view 6103:ISBN 5982:link 5962:ISBN 5921:i60A 5912:90°. 5909:Bolt 5903:The 5707:ISBN 5562:The 5322:/5.6 5310:/5.6 5302:/6.3 5256:90.7 5173:See 5158:BCPS 5054:⋅t⋅S 5044:rule 5005:for 4451:for 4243:and 3907:rate 3766:(90) 3753::11 3726::11 3717:(95) 3704::16 3693::11 3677::16 3666::11 3655::22 3644::16 3628::22 3619:(96) 3617::16 3606::32 3595::22 2605:140 2602:190 2599:250 2596:260 2593:320 2326:and 1929:loss 1917:loss 1892:19.0 1699:gels 1492:6400 1487:3200 1482:1600 1346:/1.8 1307:53% 1281:66% 1255:74% 1191:Metz 1163:Sony 893:12.0 621:and 476:The 447:(in 389:/2.8 379:/2.8 364:/2.8 245:30 m 219:feet 215:feet 164:and 61:/1.4 7500:CCD 6281:toy 6276:TLR 6266:SLR 5805:two 5703:331 5315:+⅓) 5288:/11 5248:328 5240:270 5193:/11 5166:ISO 5042:/16 5009:125 4979:lux 4977:in 4621:256 4609:/32 4595:/16 4479:400 4475:200 4471:100 4455:125 4406:lux 4404:in 4311:/11 4292:125 4286:/11 3974:Lux 3883:Phi 3734:20 3685:15 3636:10 3475:/11 3402:125 3337:250 3262:200 3209:/11 3199:125 3146:/16 3128:250 3123:236 3118:200 3113:170 3108:148 3103:120 3098:100 2974:250 2899:200 2846:/11 2836:125 2783:/16 2695:6.5 2576:400 2565:200 2554:100 2491:400 2441:400 2427:400 2330:200 2283:800 1739:0.5 1477:800 1472:640 1467:500 1462:400 1457:320 1452:250 1447:200 1442:160 1437:125 1432:100 1158:285 1089:9.0 572:256 541:not 510:lux 351:). 239:two 174:or 68:/22 54:/16 33:120 7817:: 6042:47 6002:^ 5978:}} 5974:{{ 5948:^ 5940:: 5858:): 5815:): 5794:^ 5757:): 5737:): 5721:^ 5705:. 5671:^ 5593:, 5507:. 5424:, 5390:, 5338:, 5336:/8 5331:, 5297:, 5295:/8 5290:, 5150:GN 5126:20 5065:. 5058:/f 4985:; 4597:, 4590:, 4583:, 4581:/8 4576:, 4569:, 4567:/4 4562:, 4555:, 4553:/2 4548:, 4541:, 4498:/8 4473:, 4412:; 4288:, 3587:6 3482:/8 3347:/8 3342:@ 3285:) 3283:+⅓ 3279:/8 3272:/9 3267:@ 3204:@ 3141:@ 3136:60 3093:85 3088:72 3083:60 3078:50 3073:39 3068:33 3063:26 3058:21 2984:/8 2979:@ 2922:) 2920:+⅓ 2916:/8 2909:/9 2904:@ 2841:@ 2778:@ 2773:60 2765:76 2760:72 2755:60 2750:52 2745:45 2740:36 2735:30 2730:26 2725:22 2720:18 2715:15 2710:12 2705:10 2659:60 2620:15 2579:th 2568:th 2557:th 2546:th 2543:50 2535:th 2532:25 2502:. 2477:50 2462:. 2451:25 2372:25 2347:. 2320:60 2312:. 2055:1/ 2042:2/ 2031:1/ 2018:2/ 1997:2/ 1952:1/ 1894:. 1888:32 1825:32 1427:80 1422:64 1417:50 1412:40 1407:32 1091:. 1057:32 1051:51 895:. 889:48 853:16 847:48 627:. 574:). 561:, 554:, 429:/4 420:/4 411:. 409:/4 349:/8 342:/8 328:/8 321:/4 311:/4 301:/4 223:ft 221:, 203:: 190:34 186:SI 117:. 87:GN 47:/8 40:/4 29:37 6199:e 6192:t 6185:v 6044:. 5984:) 5970:. 5923:: 5896:( 5854:( 5777:( 5753:( 5733:( 5715:. 5629:n 5620:2 5495:) 5490:5 5481:2 5453:3 5450:1 5444:5 5435:2 5410:6 5401:2 5376:7 5366:2 5361:( 5348:f 5341:f 5334:f 5327:f 5320:f 5308:f 5304:( 5300:f 5293:f 5286:f 5262:) 5253:= 5244:/ 5235:( 5191:f 5122:O 5119:S 5116:I 5110:S 5107:P 5104:C 5101:B 5094:= 5091:N 5088:G 5062:k 5056:) 5052:v 5050:E 5048:( 5040:f 5035:" 5022:v 5020:H 5007:/ 4998:t 4993:) 4969:v 4967:E 4944:v 4940:H 4936:= 4933:t 4925:v 4921:E 4900:1 4897:/ 4894:1 4877:t 4874:= 4868:S 4860:v 4856:E 4849:k 4839:2 4835:f 4807:v 4803:E 4799:= 4793:S 4787:t 4781:k 4771:2 4767:f 4741:S 4738:= 4732:t 4724:v 4720:E 4713:k 4703:2 4699:f 4673:f 4670:= 4664:k 4660:S 4654:t 4646:v 4642:E 4616:k 4611:) 4607:f 4600:f 4593:f 4586:f 4579:f 4572:f 4565:f 4558:f 4551:f 4544:f 4537:f 4520:n 4511:2 4496:f 4491:8 4486:f 4481:) 4466:S 4453:/ 4444:t 4396:v 4394:E 4373:k 4370:= 4363:2 4359:f 4354:S 4348:t 4340:v 4336:E 4309:f 4290:/ 4284:f 4266:( 4094:. 4003:v 4000:H 3966:v 3963:E 3926:v 3923:Q 3887:) 3878:v 3875:Φ 3814:2 3772:f 3761:f 3750:f 3739:f 3723:f 3712:f 3701:f 3690:f 3674:f 3663:f 3652:f 3641:f 3625:f 3614:f 3603:f 3592:f 3480:f 3473:f 3414:/ 3345:f 3335:/ 3277:f 3274:( 3270:f 3207:f 3197:/ 3144:f 3134:/ 2982:f 2972:/ 2914:f 2911:( 2907:f 2897:/ 2844:f 2834:/ 2781:f 2771:/ 2700:8 2657:/ 2618:/ 2574:/ 2563:/ 2552:/ 2541:/ 2530:/ 2528:≥ 2489:/ 2475:/ 2449:/ 2439:/ 2425:/ 2388:/ 2370:/ 2328:/ 2318:/ 2281:/ 2277:v 2274:Q 2218:y 2214:x 2203:3 2185:n 2161:O 2158:S 2155:I 2149:a 2146:r 2143:e 2140:m 2137:a 2134:C 2131:= 2126:n 2122:2 2115:O 2112:S 2109:I 2103:h 2100:s 2097:a 2094:l 2091:F 2066:3 2057:2 2044:3 2033:3 2020:2 2010:1 1999:3 1988:3 1986:/ 1976:2 1967:2 1965:/ 1954:3 1943:3 1941:/ 1872:x 1844:y 1840:x 1807:n 1783:N 1780:G 1774:d 1771:e 1768:r 1765:e 1762:t 1759:l 1756:i 1753:F 1750:= 1743:n 1730:N 1727:G 1379:/ 1344:f 1335:/ 1120:( 1073:x 1055:/ 1033:x 1007:N 1004:G 998:r 995:e 992:w 989:o 986:p 980:d 977:e 974:c 971:u 968:d 965:e 962:R 959:= 954:x 946:N 943:G 937:r 934:e 931:w 928:o 925:p 919:l 916:l 913:u 910:F 873:x 851:/ 829:x 807:y 781:N 778:G 772:r 769:e 766:w 763:o 760:p 754:d 751:e 748:c 745:u 742:d 739:e 736:R 733:= 727:x 722:/ 717:y 708:N 705:G 699:r 696:e 693:w 690:o 687:p 681:l 678:l 675:u 672:F 570:/ 565:8 563:/ 558:4 556:/ 551:2 427:f 418:f 407:f 387:f 377:f 362:f 347:f 340:f 326:f 319:f 309:f 299:f 272:. 249:/ 229:( 208:. 179:. 85:( 66:f 59:f 52:f 45:f 38:f

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Index