(EOS R) Can I focus -while- holding the Depth-of-Field Preview Button?

[vanillaslice]

Hey all,

I've been using the EOS-R for almost a year and now my only issue with the camera is being unable to focus while using DOF Preview. I've used Canons DSLRs in the past and used the feature frequently. I find it extremely beneficial being able to see what is exactly going to be in focus before I take the photo.

I'm aware that you need to bind DOF Preview to a button, and I've done that. However I'm not able to focus while holding the button down. Making it a really clunky process of repeatedly pressing it as I make adjustments to the focus. Is there anyway of keeping the lens stopped down while focusing?

It works in video mode, so I don't see why this shouldn't be available while taking photos. I am aware that the EOS R keeps the aperture fully open to make it easier for AF, MF, Exposure Simulation, ect...

Any help would be appreciated, thanks guys!