Depth of Field, Part 3
So, what can you do now that you know how to control depth of field?
In landscape work, we often try to achieve maximum depth of field and many people just stop the lens down to its minimum aperture and fire away, not really knowing if this will work or not until they get their film back. Did you know, however, that excessively small apertures actually decrease image sharpness due to diffraction? A much better approach would be to make use of the depth of field preview to stop down only far enough to achieve your desired result.
In wildlife work, we often want to have a shallow depth of field so that distracting background elements are softened by being thrown out of focus. Simply shooting at your widest aperture though may not give you enough depth of field to even have your subject in focus. To determine what aperture will work to get the best shot, use your depth of field preview control.
Controlling depth of field can be extremely important for more intimate landscapes and close-ups. Taking your time to fine tune your image DOF can make the difference between capturing a great shot and one that is destined for the trash bin. Suppose for example you are shooting some flowers and you are fighting a slight breeze. Too little depth of field will probably result in out of focus flowers, whereas too much depth of field will result in blurred flowers from the wind. How do you find that ideal aperture to allow you maximize your chances of getting the shot? You guessed it, by using your depth of field preview.
With practice, you may not need to do so on every shot, but checking the depth of field with the DOF preview is a great way to improve the quality of the images you come home with. Learning to use it effectively can be key to producing quality results.