I have read and re-read the handbook for my 40D and numerous articles that talk about autofocus modes. I understand the differences between the three modes but what I cannot understand is why I would want to select One Shot or Servo since AI switches between the two as appropriate. Why would would I not want to leave the camera set to the AI mode? Thanks Ken
Because what the camera thinks is appropriate might not be what *you* think is appropriate. 8^).
About the only situation I can think of is this: Say you want to take multiple shots of a drag race. If you focus on the car and hit and hold the shutter as the light turns green, the camera might not swich to Servo mode.
In one shot mode you can lock focus (and/or exposure) by 1/2 depressing the shutter. There are times when you might want that. You might want to focus on something and hold that focus, even if other subjects move around.
It's basically a case of the camera doing exactly what you want (and expect) it to do rather than having the camera decide on what it should be focusing on and whether it should track that object if it decides to move (or something else moves that the camera thinks might be your main subject).
Author
Logged
