Blackmagic Forum

WHile filming outside, i was using my Canon 24mm L lens. and no matter what settings i changed without an ND filter the footage was super blown out could barely see anything. I switched lens to a Tokina 11-16mm and without the need of a ND filter the footage looked amazing. Why would that be?? I even tried using the Canon on f22 nothing, while the Tokina was only at f15; Am i missing something?

Iris stuck?

Thats the thing, its working fine. i can press it and go up and down the f stops on the Canon, but no matter what even f22 is super overexposed.

Did you look at the recorded footage? Before putting film on my screen the reflections made everything look super blown out.

Yup, and it looked exactly how it was on screen terrible. I filmed from inside looking out, and from just standing outside and filming. The 24mm both times failed and was super blownout.

Thanks for brining this up,

I had the same issue with another canon lens 17- something (Forgot what it actually was as it was my friends)

I was able to go up and down with the fstop but the iris did not respond... I believe its a communication issue

Marcel Beck wrote:Thanks for brining this up,

I had the same issue with another canon lens 17- something (Forgot what it actually was as it was my friends)

I was able to go up and down with the fstop but the iris did not respond... I believe its a communication issue

17-55??? thats so crappy especially since i was considering getting that lens as well lol. I hope that this issue is fixed i love my 24mm but right now if anything is done outdoors an ND is necessary, and it still doesn't correct it 100%.

Cognizantphotos wrote:

Marcel Beck wrote:Thanks for brining this up,

I had the same issue with another canon lens 17- something (Forgot what it actually was as it was my friends)

I was able to go up and down with the fstop but the iris did not respond... I believe its a communication issue

17-55??? thats so crappy especially since i was considering getting that lens as well lol. I hope that this issue is fixed i love my 24mm but right now if anything is done outdoors an ND is necessary, and it still doesn't correct it 100%.

Not sure, will find out this week which lens it was exactly.

There is a temporary fix, if you have a DSLR put your 24mm on it, set it to a F-stop, then remove the lens and attached it to the BMCC, its tedious but at least you get to use your lens! (works but I haven't tried)

We have a Canon EFS 17-55mm and it works great.

f numbers are not absolutes remember.

My Canon EFS 18-55 works like a charm .....

I haven't tried my 50mm 1.4 but i can say with certainty on more then one occasion, the 24mm L does not work how it should. Works perfect on any Canon dslr i've tried it with, but def not the BMCC.

My Canon EF-S 17-55 f2/8 responds perfectly as well..
Perhaps you are talking about the Canon EF 17-40 F4 L lens.. which will show the f-stops moving on the LCD.. but it does not move the aperture on the lens.

Any updates i never updated to 1.4 can anyone confirm that the Canon 24mm L works any different?

I have a Canon 16-35mm f/2.8 L lens and the aperture doesn't doesn't respond on the BMCC, but my Canon 17-55 f/2.8 IS and my Canon 17-85mm's do respond. In fact my Canon 16-35mm lens is the only lens that I've tried that doesn't respond to aperture changes.