Why doesn't my 5D markIII focus

[shaylou]

Hello all,

I set my camera to live mode locking the mirror, connect a canon trigger remote (cable release) and push the remote button to focus but nothing happens. The only thing that I can think of is that I moved my focus button to the back of my camera, It is no longer on the shutter button. Is this normal or is there a setting that I overlooked? At this point I had to push the back focus button to lock focus and then push the remote to fire the shot.

 

[Canon Bob]

You're correct, remote cord focussing requires that the body is set up to focus on a half press of the shutter button and not on the AF button.
For static subjects, you can manually focus or use the AF button and then flick the lens' AF-MF button to MF and the remote cord will work okay.

Bob

 

[shaylou]

You're correct, remote cord focussing requires that the body is set up to focus on a half press of the shutter button and not on the AF button.
For static subjects, you can manually focus or use the AF button and then flick the lens' AF-MF button to MF and the remote cord will work okay.

Bob

Thanks Bob. Last night I used the back button to focus and did not turn the lens to manual focus and it seemed to hold focus just fine. That leads me to the question of do I really need to be switching my lens off and on? I can't think of anything that would activate the focus from that point,

 

[Canon Bob]

Thanks Bob. Last night I used the back button to focus and did not turn the lens to manual focus and it seemed to hold focus just fine. That leads me to the question of do I really need to be switching my lens off and on? I can't think of anything that would activate the focus from that point,

For a quick shot then it's correct that using the AF button will allow a subsequent shot. I do however believe that the focus confirmation times out eventually....it certainly used to on older bodies.

Bob

 

[graphilly]

Thanks Bob. Last night I used the back button to focus and did not turn the lens to manual focus and it seemed to hold focus just fine. That leads me to the question of do I really need to be switching my lens off and on? I can't think of anything that would activate the focus from that point,

From what Bob says you will need to if you focus and then recompose. In live view it won't matter because you are just refocusing on the same spot.

I use back button focus to help me avoid having to switch the lens on and off all the time, but I use a wireless trigger so don't have the same problem as you.

 

[shaylou]

Great thanks for the help guys, you cleared that up for me.