For a few minutes today, the Canon 17-120mm cine lens started talking with the AF on the Mark II. I was rolling on an interview, after doing a lot of handheld all morning. The "MF" icon flashed a few times in the LCD display, then the auto focus box popped on and was functioning as normal. I was adjusting focus and it was working, the arrows were moving and the box was turning green when the image was focused properly. I moved the box around the screen and it still worked.

But, after a minute, it all went away. Then, I got an error message that the lens wasn't communicating correctly. Now, every time I power up the camera there is a lens error message that I have to clear, and a tiny red box in the left of the LCD display that reads "lens".

I also noticed a little play in the lens mount at the end of the day. I also had removed the cine lens first part of my shoot to use some L glass, then went back to the cine lens. after the first hour. It was weird and I haven't had a chance to troubleshoot it. Maybe tomorrow.

Is is supposed to talk to the camera? Canon was pretty clear that the cinema lenses wouldn't work with the focus assist features (although I'm not sure about that zoom)...and I've never seen the focus indicators show up with my cinema primes (although I've been enjoying the autofocus so much, I don't bust them out as often as I should.

Barry

Yeah, I think I have a malfunction going on. But, it was definitely working with the cine zoom. Which, of course, makes me think it is a function that may work in a future firmware update.

I don't know the magic behind Canon's focus assist. I am taking a guess and saying the system works using part lens hardware and part camera hardware. I would then guess that only the camera-side of the focus assist was working, somehow the camera thought the lens was doing it's share too. This is my non-educated stab at a reason it worked, though.

So, even if it was half-working... it worked pretty well... so maybe Canon can turn it on with the cine lenses, too...?

You might try cleaning the contacts. I don't know how it's designed to function, but cleaning the contacts might make its behavior consistent.