My 70-200mm 2.8L IS works great on the 5D. Having just acquired the C100 DAF I was excited to try the lens. Turns out it's possessed. Sometimes it will work a bit, but eventually the iris locks at "f1" and the zoom mm designation is nuts, too (like 9mm) and then the iris periodically flashes like mad. See below.

The contacts seem fine (?). I've barely used the lens, actually, and as i mentioned, it seems to work fine on my 5D...Is this a C100 compatibility thing? I just updated the firmware...no lens firmware that I can find.

Lens possession on Vimeo

I have the same lens and camera and once something similar happened but not as drastic as on your video. I had a little flicker as if aperture changed within one f-stop. I turned the camera off and back on and it went away. This happened once on a year and a half I've owned this equipment.

Is this the original or the "II" version of the 70-200?

I use the Canon EF 70-200mm f/2.8L IS II USM Lens all the time on my C100s, and I've never had any problems.

Either ways, something is wrong. I'd contact Canon service. You're talking about $7K in gear (or more). It should work properly when you need it to.

Lens is v1, and I've sent it in for a check up. I put this video together to show them, but they didn't need it. I don't think I've discovered anything new and unique - it's a very popular lens + camera combo. I'm not ahead of the curve, here, so I'm going with lens first. Maybe it's both, but only together? Ah well, not ready to send in the camera. I have a hard time believing it's the C100, auto + new firmware issue...but I've been wrong about bigger things.

70-200mm on Vimeo

Kathy, thanks.

I'll report back with the update on the lens...just odd the way it ramps up to total freakage. A lens issue "feels" like it should be on/off. A camera issue, same kind of thing. Oh well, we shall see!

Waiting for FedEx to deliver the "fixed" lens...it seems if they can't find you on a Saturday, they wait 3 more days to punish you.

Well, that didn't fix the issue. Despite being certain that it just *had to be the 70-200mm, it isn't. They're escalating this to some ENGs to see what they think before we ship everything (as in lens + brand new C100) back...

I'm not sure if it helps at all but I have the same lens and it works well with my C300 after the DPAF update. I haven't had my C100 updated so I can't test that I'm afraid.

Thanks for chiming in, Paul.

I haven't been able to find anyone else who *does have the issue. I'd love to co-miserate but apparently I am the chosen one.

Jeff I'm sure this isn't related not your F-Stop issue but I've seen on my IS lenses that when I work close to powerful radio transmitters the IS screws up completely. Another thing to add to our list.

Kind of acts like a low power feed to the lens. Certainly the camera is giving you incorrect readings. Does it also happen on AC Power? Always difficult to trouble shoot something like this without eliminating the camera side of the equation as well. Can you borrow another lens locally to see if you can duplicate the issue?

I borrowed another 70-200 to test - worked fine...don't know what that means!

More likely this lens doesn't like your C100 for some reason.

Without a second thought this is the lens to have. A must have for any professional photographer looking to max out his or her arsenal. A key piece of glass that will not only expand your skills but increases your overall performance as a photographer. Great in low light, ideal for concert photographers, incredible bokeh. Grab this lens ASAP.

Well, it's finally back! The lens seems to be in good working order with my C100 now. 37 days, counting weekends may be normal - but it felt like forever! Oh yeah, that's not even counting the first "repair" of just the lens.

No reason given as to what was wrong, but whatever it was, they found it. ... It's been set up by my desk for a while now and it seems stable. I'll give it a harder workout later...

tl;dr A 70-200mm lens was whacked out of it's mind on a new DPAF C100 but functioned fine on a 5D Mark II. It also apparently worked fine on other C100s and other 70-200s worked fine on this C100. Bad Mojo purged by Canon.