Bracketing

Calculating correct exposure can sometimes be difficult. Nobody can determine correct exposure all the time. This is especially true if you are working with a scene that includes very bright or very dark tones, or when working under uneven light. When photographing a middle tone subject under bright sun, calculating exposure is simple. You can trust your meter if it's been calibrated correctly or just use the Sunny f-16 rule. Even darker and lighter subjects are easy to meter under normal light if you open up or close down from your meter reading to compensate for the lighter or darker tones. However, there are times that you can't be sure of the correct exposure. You can use bracketing whenever you are in doubt. Bracketing is a series of shots taken of the same subject by varying the exposure. For instance, If your meter reading indicates 1/60 sec at f-11 for a scene, and you want to bracket one full stop you would shoot at 1/30 sec at f-11, 1/60 sec at f-11, 1/125 sec at f-11. This is a three exposure bracketing. You could add 1/15 sec at f-11 and 1/250 sec at f-11 for a five exposure bracketing. I prefer bracketing in half stops with slide films. You can see a big difference when working with slide films even by opening up or closing down 1/2 stops. Many photographers even bracket in 1/3 stops. Print films don't show that much difference when bracketing 1/2 or even one full stops. Plus, bracketing is not very important with print films. You can always correct exposure during processing. Slide films are not forgiving. If you make a mistake, you can't always correct your exposures especially if you overexpose an image too much.


Above Image: Due to large white area, I bracketed the shot +/- 2 stops from the suggested camera exposure reading. Canon EOS A2, Tokina 20-35mm ATX lens, Fuji Velvia 50, Bogen tripod and ball head.

You can't bracket shots when you use program, aperture-priority, or shutter-priority modes by changing shutter speeds or aperture. The camera automatically adjust settings to give what it thinks is the correct exposure. For example, if you set your camera on aperture priority and take a meter reading that gives 1/60 sec at f-11, if you change to f-8 to add more exposure, your camera will change the shutter speed to 1/125 sec which gives the same exposure as 1/60 sec at f-11. You must use exposure compensation dial (+/- dial or button) to vary exposure. Take a shot at zero setting and then set compensation dial to +1/2 if you want to bracket in half stops or +1 for full stop bracketing. Take another shot at -1/2 or -1 setting. Continue bracketing up to +/-2 stops. This will ensure at least one good exposure. Some photographers believe bracketing is a waste of film and used by less advanced photographers who don't know how to properly meter a subject. I don't agree at all. I have spent a lot of money on equipment, and time finding good subjects. I want to come back with a few well exposed images. I know what camera, lens, or film I need to use most of the time, but not all the time. I also know how to calculate the right exposure for many of my subjects under different light, but many times I simply can't be sure. Bracketing gives me a few good images. I don't care if I waste film and I'm not trying to impress other photographers. I recommend bracketing your shots whenever you're in doubt. A frame of slide film costs only 30 cents. It is well worth a once in a life time shot.

The "Auto-Exposure Bracketing" button as shown below the green dot in the picture to the right, allows you to shoot your images at a selected over or under exposure value (+/- EV).

To adjust, set the bracketing value, and select the number of frames to bracket, up to 9 shots can be selected in some models.

 

Recommended reading: Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera More than 100 vivid, graphic comparison pictures illustrate every point in this classic and can help any photographer maximize the creative impact of his or her exposure decisions. Peterson stresses the importance of metering the subject for a starting exposure and then explains how to use various exposure meters and different kinds of lighting. The book contains lessons on each element of the triangle and how it relates to the other two in terms of depth of field, freezing and blurring action, and shooting in low light or at night. A section on special techniques explores such options as deliberate under-and over-exposures, how to produce double exposures, bracketing, shooting the moon, and the use of filters. Understanding Exposure demonstrates that there are always creative choices about how to expose a picture - and that the decision is up to the photographer, not the camera.