bracketing

Bracketing is quite simply making extra exposures in addition to the one that you think is probably best. It is called bracketing because traditionally, you would shoot one exposure at your best guess and then two more, one at more than the best guess and one at less (the 'brackets'). Sometimes, though, you don't need to shoot both an over-bracket and an under-bracket; you just shoot one other picture at a different exposure.

the best guess

Regardless of whether you are shooting slide, digital or negative, you will obviously make a 'best guess' at exposure with whatever tools are at your disposal: in-camera meter, spot meter, incident-light meter or sheer guesswork. Often you will combine two or more: your best guess may differ quite significantly from the meter reading. Then you may decide to bracket as well.

Palms, Goa

Reflections are notoriously tricky to meter: in such a situation, bracketing may make eminent sense. Roger used a Leica M4-P with 35/1.4 Summilux for this shot. Right, top to bottom: one stop over, best guess, one stop under. Left, the middle exposure.

 

an admission of incompetence?

Some people decry bracketing as an admission of incompetence. "If you were any good," they say, "you wouldn't need to bracket." Sometimes there is some merit in this: there may be little or no reason to bracket. But equally, a refusal to bracket may be an admission of stupidity or arrogance. Which is better: to admit that you aren't sure what the best exposure is, or to miss the picture?

Besides, if you look at the work of those who are most vocal in their condemnation of bracketing, you very often find that the reason they don't need to bracket is that they will put up with almost anything in the way of exposure. They are the ones who don't know what they are doing: if they did, they would bracket, at least sometimes. One of the reasons they don't bracket, of course, is that they don't realize how much better a picture might look if it was correctly exposed.

 

 

 

Hat and light bulb

Yes, this was bracketed. Too much exposure and the hat would 'blow'; too little, and you'd lose all the texture in the background. A spot meter would have solved the problem but we didn't have one in those days -- so Roger bracketed, shooting Fuji RFP in a Nikon F with a 70-210/2.8 Sigma Apo.

why bracket? 

There are at least five reasons for bracketing. The first is if you are using an unfamiliar film or developer. The second is because you are unsure of the correct exposure. The third is when you are unsure which exposure will give you the best effect. The fourth is when you don't have time to meter properly: it's quicker to bang off several pictures. The fifth is when you want a set of precisely matched transparencies.

1  unfamiliar film or developer

When you shoot the first roll of a new film, it makes a lot of sense to bracket. Although ISO speeds are extremely reliable if you are shooting under ISO conditions, you may well find that a particular film gives you better results at a different exposure index (EI). For example, we habitually rate Paterson Acupan 200 at EI 160 or even 125 -- though to be accurate, these are probably more realistic ISO speeds in many developers than 200, which is achievable only with a speed increasing developer. When we use Fuji Acros, nominally ISO 100, we shoot at 64: we find the tonality vastly superior. And many people shot the original Fuji Velvia (ISO 50) at 40 or even 32.

A lot depends on the developer, too. As explained in the free module on ISO speeds and the paid module on choosing developers, fine-grain developers can wipe a stop or more off the ISO film speed and speed-increasing developers can add two thirds of a stop or (rarely) more. For that matter, even the development regime (especially agitation) can make a difference.

Ladder, La Buttiere

Even with familiar films and familiar developers, you may do well to bracket if you use an unfamiliar combination of the two or a new development regime. This is Ilford Pan F in Ilford DD-X, deliberately developed to a very high contrast in keeping with Mortensen's theories. The best exposures were at around EI 200, a two-stop push. Roger used a Nikon F with a 200/3 Vivitar Series 1 and a 2.8x Soviet-era orange filter.

2  unsure of the correct exposure

Suppose you usually shoot landscapes, but you want to try your hand at a few portraits. You may be able to expose landscapes perfectly, but not be 100 per cent sure about portraits. So bracket.

Even with familiar subjects, there can be tricky exposures. To take a simple example, imagine that you are photographing a snow scene. Ideally you want an incident light meter, or failing that, a limited-area reflected light meter, even one as primitive as an old Weston Master.

But you don't have one with you. You have only your through-lens camera meter. With any broad-area reflected-light reading, including a through-lens meter, you know that the meter will recommend under-exposure. You therefore decide to give about two stops less than the meter indicates. You bracket this at +/- 2/3 stop for slide or digital, or you make one extra exposure at +2 stops for negative. Then there are scenes with a very long brightness range, like the example below.

Thari, Rhodes

This is as close to an impossible-to-determine exposure as you can easily find. The brightness range is immense and you want as much detail as you can get in both highlights and shadows. Today, we would solve the problem with a spot meter, keying the exposure to the brightest area in which we wanted texture -- but in those days we didn't have a spot meter. Perhaps needless to say, we couldn't get close enough to the altar to take local readings. The answer? Shameless bracketing, at half-stop intervals (with a 35/1.4 Summilux on a Leica M4P) across -2 to +2 stops from the best guess. Yes, 9 frames to get one shot -- but would you want to miss the shot? As it turned out, at least 3 shots were perfectly usable. A lower-contrast film than Fuji RFP would have been nice but that's what we had with us...

3  unsure of the best effect

Again to take an example, you are photographing a young dancer in a rehearsal room. You have a pretty good idea of what the 'correct' exposure would be, but you suspect that perhaps you will get a better picture if you over-expose slightly. You therefore take one exposure at your best guess and another at 1/2 or 2/3 stop more. You know there is little point in cutting the exposure so you don't. This is on slide or with a digital camera, of course: with negative film, you make the adjustment at the printing stage.

 

 

Ruin, Portugal

Roger wasn't sure whether the picture would look best with the shadow very dark, or as light as it could be and still be a good shadow. The solution was to take two pictures, one aiming at each effect -- but there was no need for a third bracket. This is the one with the light shadow. Voigtlander Bessa-R2, 35/2.5 Colour-Skopar, Kodak EBX ISO 100.

4  no time to meter

The way that most experienced Leica photojournalists work is to have the camera pre-set at a likely exposure for the prevailing conditions. If there is time, and if it won't make them too conspicuous, they may meter; but otherwise, it's a question of putting the camera to the eye, focusing and shooting, then bracketing if possible.

 

 

 

Man with umbrella, Portugal

 

Roger shot this with a Leica M4-P (which does not have a built-in meter) and a 35/1.4 Summilux. The camera was pre-set to 'typical' conditions, basing the exposure on an incident light reading taken with a Gossen meter. Auto-exposure would have under-exposed the scene even worse, being fooled by the white walls. There was no time for a second bracket which would have been at 1 stop more.

5  precise matching

This one is seldom a concern for most people, and it was more important before the rise of digital, but it is still worth knowing about. You are shooting a series of transparencies on related but not identical subjects; some, but not all, are against the same background. To be absolutely sure of matching transparencies you shoot at -2/3, -1/3, 0, +1/3, +2/3. You are now within 1/6 stop across a range of +/- 3/4 stop.

bracketing for different media

Bracketing is most usually associated with shooting slides, because until the advent of digital imaging, this was the most critical medium for metering. An under-exposed slide is murky and dark, often with 'blocked' (solid black) shadows, and an over-exposed slide is washed out, often with 'blown' (solid white) highlights.

Even so, there is normally some latitude for over- and under-exposure. Sometimes there is only one exposure that 'sings', but surprisingly often with modern slide films you can get way with as much as a stop over or under, with two or even three pictures that are all completely acceptable or excellent.

Vegetable stall, Udaghamandalam (Oootacamund)

Night shots, despite their very wide tonal range, are often surprisingly uncritical and a range of two or even three stops may deliver entirely acceptable exposures. This is probably because we can fairly easily accept both 'blown' highlights and 'blocked' shadows, provided they do not occupy too much of the image area. Fast films -- this is the late, lamented Ferrania/3M ISO 1000 daylight film -- have more latitude than slower ones, too. Roger used a Leica M4-P and 35/1.4 Summilux, guessing the exposure and then bracketing +/- 1 stop. Digital sensors at night can however be very limiting indeed because of the ease with which highlights 'blow'.

Digital sensors have even less latitude for over-exposure than slides, though they may have a little more latitude for under-exposure, if you are willing to manipulate the image in Adobe Photoshop or something similar after you have taken it. Negatives are much less critical. This is equally true in both black and white and colour. You can make quite large changes to the brightness of the final print, whether you make it in the traditional wet darkroom or digitally. Negatives have comparatively little latitude for under-exposure, but enormous latitude for over-exposure.

Contrary to popular opinion it is quite hard to over-expose a negative sufficiently to 'blow' the highlights, at least if you are printing conventionally, though a very dense negative may defeat some scanners that cannot handle high maximum densities. Even then, a stop or more of extra exposure is unlikely to be a major problem.

slide and digital bracketing

From experience and from theory, we believe that the optimum bracketing step for slides and digital in most cases is +/- 2/3 stop. This is based on the fact that normally, an exposure to the nearest 1/3 stop is regarded as spot on: in fact, it is the smallest step that many cameras can manage.

If you have judged the exposure perfectly, the 'over' (+2/3) and 'under' (-2/3) exposures are irrelevant: the middle exposure is all you need. If you are wrong, you will necessarily be within 1/3 stop across a range of +/- 1 stop in each direction: 2/3 stop bracket + 1/3 stop error. Unless you are more than 1 stop out in either direction, the biggest error you can have is exactly half way between the middle exposure and one of the brackets, which is 1/3 stop.

 

War Memorial, Moncontour

Digital cameras -- this was a Nikon D70 with standard 18-70 zoom -- are the most critical of all for exposure. The metered exposure (using a Gossen incident light meter) was 1/60 second at f/8. This is the exposure used for the large picture on the left, which has been lightly dodged in Adobe Photoshop. The others run in 1/3 stop brackets from 1/15 second to 1/200 second at f/8. You can see how a 1/3 stop variation in exposure is detectable, while a 2/3 stop variation is significant. At as little as 1 stop over the white stone is 'blown' and at even 1/3 stop under the poilu's face is almost too dark to save even with dodging -- and this is under very flat winter lighting The optimum exposures are probably 1/50 second (1/3 over) and 1/60 second (metered exposure), with 1/40 second (2/3 over) just about usable.

Unfortunately, many shutters and lenses do not allow easy bracketing at 2/3 stops. Few non-electronic shutters allow you to set intermediate values: M-series Leicas are an exception, though the values are not marked, and old Alpas had intermediate 1/3-stop click stops on the shutter speed dial. Many lenses are click-stopped only at full-stop and half-stop intervals, but if time is not of the essence, and if the lens permits it, try to set 2/3 stop or at least 3/4 stop brackets by interpolation between the click stops. Otherwise, unless you have a lens with 1/3 stop detents or markings, you have to choose between 1/2 stop and 1 stop brackets. With modern films, for general applications, we believe that 1 stop is a better choice, but you may feel differently. With digital imaging we would choose 1/2 stop if we had to, but fortunately, most digital cameras can manage 2/3 stop brackets.

In really difficult cases, where the brightness range of the subject is very long and you want the best possible detail in both the light areas and the dark areas, it may make more sense to use half stop rests, but make five (or more) brackets: -1, -1/2, 0, +1/2, +1. Yes, this means using five frames to get one picture. What is the picture worth to you?

 Pont en Royans -- an impossible bracket

The 'suspended houses' at Pont en Royans are fascinating, and a detail (not for the faint-hearted) is that the privies are cantilevered out to allow a long drop straight into the river. But as you can see here, with a fairly contrasty, high-saturation film (Kodak EBX), the underside of the privy is impossible to read even in the over-exposed image. The only real hope here would be VERY powerful fill flash: probably a big old flash-bulb, roughly equivalent to a 1250 Watt-second electronic flash -- and even then you might well need two of them. Leica MP, 90/4 Macro-Elmar-M. (Roger)

negative bracketing

Because negatives have such enormous latitude for over-exposure, it normally makes sense to bracket only in the direction of over-exposure. We normally make one exposure at our best guess, and another at two stops more. This may seem like an enormous bracket but it means that you are within 1 stop of the optimum exposure across a range of 4 stops (-1 to +3) -- and exposure accuracy of 1 stop is normally more than adequate for negative materials. The penalty for over-exposure is reduced sharpness and, with conventional black and white films, bigger grain, though grain with colour negatives and chromogenic black and white films will actually be finer.

 

 

Darshan Dairy, Mulund

An unusual reason for bracketing, here. Frances was worried about camera shake, so she made two exposures, one at her best guess for the minimum exposure and another at two stops more. This is the 'best guess': the other had more detail, but it also had camera shake. She used a Nikkormat FTn with a 50/1.2 Nikkor, shooting on Kodak TMZ P3200 rated at 12,500.

autobracketing

Although autobracketing sounds like a good idea, we have tried a few cameras with this feature and found it wanting. Some cameras shoot all three brackets in a burst, which does nothing for the decisive moment; if they don't, then shot 1 is the metered exposure, shot 2 one bracket, shot 3 the other. If you forget that the autobracket is on, and only shoot one frame, you have a problem; likewise if you only shoot two out of the three pictures. Also, we usually meter manually so autobrackets aren't that much use anyway if they only work with auto-exposure.

bracketing via film push/pull

This is a semi-obsolete technique, but one that is worth knowing about. You are shooting (let us say) 8x10 inch transparency. You have made a Polaroid; you have an excellent idea of the exposure. Even so, you shoot two identical sheets.

The second sheet is both an insurance and a bracket. If the first sheet is lost or scratched or otherwise comes to grief, you have it as a back-up. And if, after processing, the first sheet is a fraction of a stop from what you think would have been the perfect exposure, you order a push or pull on the second sheet: 'push half' or 'pull one third', whatever you think appropriate. Small variations (2/3 stop or less) will not result in significant variations in contrast or colour.

The usual instruction to the lab is 'process one -- hold one.' Perhaps needless to say, only good professional labs offer this as a normal service.

Unlucky pfennig

 

A still life about a spy, obviously: the currency is all British except the 1941 Nazi pfennig (enlarged, above). Roger shot this with a 4x5 inch Linhof Technikardan and 210/5.6 Rodenstock Apo-Sironar-N. Film is Fuji RDP2, shot 'process one -- hold one'.

clip testing

A variation on bracketing via speed adjustment, when you are shooting in a studio on roll-film or 35mm, is clip testing. You shoot a few frames on the first roll -- two or three on 120, maybe 5 or 6 on 35mm -- either of the subject or of a stand-in for the subject (an assistant in place of a hired model, for example). These should not be important final shots: they are an exposure test only.

You then ask the lab to clip test this roll. After seeing the clip test you decide whether to have the remaining shots processed normally or with a small push or pull.

the bottom line

Bracketing is neither difficult nor particularly expensive -- and it certainly is not an admission of incompetence. But it is quite easy to get into the habit of bracketing more than you need to: it is not something you should need to do all the time. When in doubt, of course you should bracket; the trick lies in not being in doubt any more than strictly necessary. As ever, the best way to do this is via experience, i.e. by shooting more pictures.

books

If you have found this module informative, you may wish to look at the following books:

Black and White Handbook

Perfect Exposure

Quality in Photography

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© 2006 Roger W. Hicks