I just set my AF to single instead of continuous or auto, that way it locks the focus and I can recompose.
That's how I have mine set. When I press the AF-ON button the camera will focus, but it will lose its focus after a few seconds while I'm recomposing. The focus doesn't appear to truly "lock" unless I physically hold down the AF-ON while I'm recomposing. So I'm just wondering if that's what you guys are doing - holding down the AF-ON button while you recompose - or if I have a setting somewhere that I need to adjust so that I don't have to hold mine down.
Here's another question/scenario: Can I use the AF-ON and AE lock (*) buttons individually on the same shot? For example, point at one subject, press the AF-ON button to lock focus, then recompose on another subject, press the AE lock button to lock exposure, and then finally recompose again and take the shot?