Kenneth William Caleno wrote to me about a neat way to use auto focus for wildlife or fast sports action. This setting lets you prefocus on a specific location, and once something comes into that specific focus distance the camera will take the image. To do this automatically you will need a remote release, preferably one on which you can keep the shutter button depressed. Set the release priority on the D200 for focus.
These are the settings for Nikon users:
Custom (pencil) menu:
Auto focus set to AF-S
AF area mode set to single
AE-L/AF-L set to AF On
Compose your shot and set the focus by aiming the centre focus icon at a exact target (Say, for example, a pre-focus point on a tree branch, where you are waiting for a bird to land) at the precise distance you want, and pressing the “AE-L/AF-L” button near the viewfinder. This will focus the lens- Now press and hold the shutter button. As soon as something comes into focus the shutter will fire, Its a very fast action, far quicker than a human reflex!
Prefocus on the determined distance where you expect your subject to be, using the AF-ON button. You do not want the shutter button controlling focus as you are pre-focusing. You only want the shutter button to fire the shutter. Once you are focused, release the AF-ON button.
Now back away from the object. Fully depress the shutter button and the camera will not fire. However when something comes into focus, the camera will start taking pictures.
This is very useful for unattended photography for nocturnal animals, birds at feeders etc. Also quite useful for motor sports as you can prefocus on a spot where say a race car will be and then the moment is arrives the camera starts taking pictures. It is much quicker this way than tracking the object and focusing at the same time, the camera reacts much quicker than the human finger.