Canon 50D AF control vs 20 AF control

[Jonathan Michael Ashton]

I have recently bought a 50D, my other camera is a 20D.
The 20D permitted me to use servo AF and then retain focus whilst re-composing this was done by selecting Custom Function 4 Shutter button/AE lock button to option 2: AF/AF lock no AE lock. I find this a handy option if the subject is relatively still but there isn't a handy AF point available, I generally use the central AF point, then press the * button and this holds focus, I recompose then shoot, retaining original exposure values.

I have not been able so far to make this selection on the 50D - has anyone been able to do this? Any feedback would be welcome.

Thanks
Jon

[Jason Franke]

I think you're looking for C.Fn IV-1 Shutter button/AF-ON button, set to "1: Metering + AF Start/ AF stop". If you want to keep using the * button instead of the AF-ON button, set C.Fn IV-2 AF-ON/AE lock button switch to 1 as well.

[Doug Brown]

It is doable, but I don't have the Custom Functions committed to memory. I do something like the above with some modification. I have the middle button on the back set to meter and AF. I have the shutter button set to meter and take the picture, but not to focus. I leave the camera in AI Servo. To focus and recompose, I press and release the middle button on the back while focused on the subject. When I release the middle button, the camera stops focusing. Then I recompose and take the photo using the shutter button. Works great.

[Jonathan Michael Ashton]

Thank you very much guys, I will give it a try

Jon