IS and Back Button AF

I don't have my manual handy, so hoping someone here can help me out. On a 5Dm3 I finally started using back button AF. In practicing with my 100 f/2.8L I got great results, but couldn't quite figure out the expected behavior of IS.

It seems that IS doesn't engage while auto focusing, and I have to map the IS Start function to the DoF preview button. Then I can focus, but have to hold the DoF preview to engage IS while actually taking the shot. Is this the norm? I'd like to be able to retain IS when holding shutter halfway, but doesn't seem to be possible.

Maybe I'm missing a custom function somewhere? But the button mapping menu doesn't show IS start as an option anywhere other than the DoF preview button.

when you half press shutter does the IS engage?

Brendo666 wrote in post #14581558
when you half press shutter does the IS engage?

Nope, but that is precisely what I would like it to do

Just double checked to make sure, no sound of the IS engaging, and it's certainly not stable (jiggled slightly). The IS on this lens is very noticable, and it does kick on with the DoF button pushed.

that is quite strange, i don not use back button focus, but i have tried it a couple of times and i recall IS engaging, and it ALWAYS engages when i half press shutter.

So... I guess when IS start is mapped to the DoF button then it disables IS from engaging with half press and during AF. I unmapped IS start from the DoF button, and then it did engage IS when pressing the shutter half way. It also engages IS when in oneshot mode when pressing AF-ON, but does not engage IS when Servo AF.

Well you are 66.66666666% there then. haha I am not much help for you as i don't have experience with back button focus but i hope someone will chime in and help!

Only that lens? Try it with another lems and see. It might just be a glitch with tha lens.

Nick

I just grabbed my 5D3 and 70-200 2.8 IS II and the IS engages in both one shot and servo using back button focus. The only settings I changed in camera were to make my dof button switch from one shot to servo and vice versa and setting only my back button to focus.

IS activates with both back button AF as well as with half press of shutter button.

Wilt wrote in post #14581743
IS activates with both back button AF as well as with half press of shutter button.

correct. You might want to recheck your custom functions once more.