Angela - Depth of Field

How to Control Depth of Field

Depth of field is controlled, mostly, by the aperture settings of a film camera lens. It can also change depending on the focal distance of the subject to your camera. With aperture settings, the larger the aperture opening (smaller f-stop numbers) and closer the focal distance, the shallower the depth of field will result. On the other hand, small aperture openings (larger f-stop numbers) and farther focal distances will equate to a greater depth of field.

Great Depth of Field and Diffraction

While any guide to photography will point out that the smallest aperture should be used any time the photographer wishes to have the greatest depth of field, this will pose two problems. The immediate problem is that you will likely need to use a tripod as the shutter speed will be long. The second issue is what is known as diffraction. Diffraction is an optical effect that will cause some softening effects that will offset any gain in sharpness due to the smaller aperture. This effect is usually negligible, particularly for standard 35mm single lens reflex (SLR) cameras that most will use for beginner photography. However, it should be noted to help you limit and avoid any softening due to diffraction. If you do not have a depth of field preview setting for your camera it would be best to take multiple photographs of the same scene using different apertures so that you can see for yourself which aperture will yield which amount of sharpness.

Source: http://www.guidetofilmphotography.com/depth-of-field.html

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