PhotoDeCal forum

For pretty much every DSLR, the camera comes preconfigured to autofocus when you half-press the shutter button.  This is the default configuration, and the vast majority of people never venture away from it (or even know that they can).

One very useful configuration is to decouple the autofocus from the shutter button.  This allows you to do either - take a shot, or autofocus - independently.  Thus you never have problems where you autofocus, then want to take another shot and have to wait for the camera to re-autofocus again, and in general you have a much snappier and more responsive camera.

Here are the instructions for a Canon Rebel XTi and Nikon D40 (the Rebel, Rebel Xt, D40x, and D50 cameras should be similar).  I don't have the time at the moment to go digging up pdf manuals for everyone's camera, but this will give you a good idea for what you want to look for in your camera's settings, and if you can't figure it out feel free to bring your camera in next class and I can show you.

For Canon Rebel series cameras, go to your Custom Function menu, and go to Custom Function 4, which should be labeled "Shutter/AE lock button".   Change this to 1. "AE lock/AF"

For Nikon D40 users, go to your Custom Settings menu and go to Custom Setting 12, which should be labeled "AE-L/AF-L".  Set this to "AF-ON".

Now you should be able to press the back button under your thumb to initiate autofocus.  Pressing the shutter button will now simply take the picture without starting up the autofocus again.  It may take a while to get used to, but I think it will be extremely revolutionary in the way you operate the camera - try shooting like this for the next two weeks and we'll talk a little bit about your experiences in class.