Since the advent of auto focus lenses, the world of photography changed forever. One of the biggest problems that armatures and even professional photographers have is obtaining a sharp image. In the days of manual focus lenses, the problem was a cumulation of a number of different things. Most often then not, it was a matter of proper technique and in some cases poor eyesight. The introduction of auto focus lenses allowed the photographer to concentrate on the composition and exposure of the image. Focus was just one less thing to worry about. As any photographer knows, a tack sharp image can make or break the shot.
Today’s cameras are so sophisticated that in automatic exposure mode and auto focus, the photographer can literally use his/her camera as easily as a point and shoot camera. And even with all this technology, I find allot of people still complaining about images being out of focus. The key here is to let the camera do the work as intended. Most cameras use the shutter button to lock focus and trip the shutter. Usually, people will compose the shot, press the shutter button partially down to lock focus, then wait before they take the shot. Between the time the focus is locked and the shutter is tripped, both you and your subject can move causing focus to be lost.
Since most cameras are set for “focus priority”, the proper technique when using the shutter button, is to compose the shot, and press the shutter all the way down. It’s ok to lock focus so the image can be seen clearer in the viewfinder, but you should release the shutter button to “unlock” focus until your ready to shoot. Once your ready, press the shutter button all the way down. The camera will instantly focus and trip the shutter. This is of course, assuming that the shutter button is set for both functions.
Another method on some cameras, is to reassign the auto focus function to a button on the back of the camera. This allows the shutter button to be used only for firing the shutter. The rear button should be used to auto focus and lock only. On a “focus priority” camera, you can compose the shot, press the shutter button all the way down, then press the assigned focus button to lock focus. Since the camera won’t fire until the image is in focus, it will find the focus and then fire automatically. It may feel uncomfortable at first, but once you get the hang of it, you will find a large percentage of your shots will be keepers. This is a method most often used by sports photographers.
One final method involves using a auto/manual focus lens to determine when the subject is in focus. On most Nikon professional cameras (F5, F6, D1, D2, D3) when used with Nikkor AF lenses, the manual focus operation can be used to lock focus. This allows the camera to fire only when the subject comes into range. The AF lens should be set to “manual” focus mode. The camera should be set to “single shot” auto focus mode. Now as long as nothing is in focus, holding the shutter but down will not fire the shutter. Once something comes within focus range, the camera will lock auto focus and fire the shutter. Sports photographers also use this method to capture, for example, a base runner sliding into home plate. The photographer can “pre-focus” where the runner will be, anticipate the shot by holding down the shutter button, and waiting for the base runner to come into focus range. The camera will do the rest.