loosing frames during aperture change is a HUGE issue! I hope the firmware in April better give us full manual control..

I'm not quite sure what you are getting at here?

D, I shouldn't have quoted you actually as I'm getting fatally infected from all that Canon bashing. I don't know how they could even sleep with all that karma ;)...

T

This is a non-issue for a non-variable aperture zoom lens if exposure lock is used, yes?

If I use my 24-70 f2.8 or my 70-200 f2.8 or any of my primes or etc., and I lock exposure, then this will never happen.

Doesn't seem like that big of a deal to me actually, sounds more like a lens upgrade is needed...

I don't know if this will help for sure, but if your filming to an SD card, try a full reformat using factory default cards. I have found that over time (about 12 uses) write speeds tend to drop significantly, a full reformat corrects this. Just too cluttered I guess. Anyways, I would try that. Also, I would suggest trying newegg.com for memory purchases, a class 6 16GB SDHC card goes for $30! Thats just my suggestion, I film on HD cards with a video camera, not sure about a digital SLR.

But isn't there still the problem of the shutter speed changing when you zoom - even when locked?

I'm not sure, I haven't used the camera for video with a fully attached Canon zoom for months.

Honestly, I have no idea, but I figured if exposure was locked, then exposure was locked, LOL. But given some of the other ridiculous things Canon has done, I guess even that assumption is subject to questioning, heh. Why would the shutter change if exposure was locked (and you weren't spinning the wheel for exposure compensation)?

I believe it is an aperture change issue.

Yes, the stuttering appears to be related to aperture change. That said, changing shutter speed in the middle of a shot can also ruin a take, just not as epically as dropping frames.

Lens upgrade isn't always an option... nor should it be. In fact, there are only a handful of constant aperture zoom lenses.
Certainly for some people, like filmmakers who can do multiple angles and takes, it isn't a big deal. For event shooters who need to zoom while recording live... it's a big deal as it basically ruins your take (shoot lots of b-roll to cut to... if it is an option).

True. I'd go for a bit of Mylar to decouple the lens. It's cheap and 100% effective.

OK fair enough, but as someone who does events, in my humble opinion at least, an f4-f6.x f-stop does not an event lens make. And there are plenty of constant aperture zoom lenses available, including the holy trinity 16-35mm f2.8, 24-70mm f2.8, and the ultimate event lens, the 70-200mm f2.8 IS. Expensive yes, scarce no.

This isn't a rebuttal of anything anyone has been chiming in with, I'm not saying it doesn't exist or it isn't a problem... Just saying this seems like a non-issue for constant aperture zooms (of which many exist) when exposure lock is used (which should be for every take). That's important info for anyone worried about this.

Good (but expensive) point... and with a 2x TCon you can get the 70-200 up to match the 100-400mm. Hmmm... that is tempting.

And don't forget the f4 series, which are the only zooms I could affort after buying my primes.

BTW: On a variable aperture zoom, if you start with the narrowest opening, nothing will change since it can't go narrower. I used that trick on my 28-135 f3.5-f5.6 until I sold it. Of course using only f5.6 sucks. I set it 5.6 and "locked the aperture" with mylar.

Something had been nagging me for a while about this post, and while I initially agreed with you, I've had to change my mind.

The problem with what you've said here, is that, yes, those are the holy trinity of even lenses........... for photography.... where you only have to snap a few shots here and there and can change lenses without interrupting your work flow.

I have a wide background of live event video, where you need to shoot continuously for half an hour to an hour at a time (if not longer), uninterrupted.... and you need to vary your focal length throughout, from wide to closeups, with the same lens. This means that the still photo "holy trinity" really dont qualify as event video lenses, since they don't have the zoom range to carry you through.

The only "serious" still camera lenses suitable for live video events would be the Canon 28-300L IS and the Sigma 50-500 (barely), neither of which are constant aperture.

Of course, there are tons of type of live events, and multi camera setups would make certain things easier and more complicated at the same time (and ignoring the 12min time limit). In a perfect world you've have 5 camera setups with 5 different lenses, but that's a different topic altogether. :)

My point is back to: The photo holy trinity of film lenses isn't a solution for live video where you can't switch lenses while shooting (ie, most single camera events), and many of us will be back stuck with the aperture "glitch". This of course isn't an issue if you are shooting multi-camera setups where you can cut to a different angle while zooming, or if you shoot enough b-roll to cut away to during zooms.

That's all.... I'm just giving a heads up.... and here I was just about to plunk down $2k on a 70-200L f2.8 IS (nah, I wasn't really, just dreaming. :) )