BMPCC and Aperture Adjustment with Speed Booster

Hi - this is my first time posting here. I am a new user of the Black Magic Pocket Cinema Camera.

I have two lenses (and older Nikon F and a new Sigma ART 18-35 f/1.8). I also have the BMPCC to Nikon Metabones Speed booster.

I had tried the Sigma and Speed booster in the store with their demo BMPCC and I was able to use the Speed booster's aperture controls to make the image brighter. On my camera, I cannot. Is there an update I need?

I got the Sigma because of the f/1.8 since I need low-light capabilities. Although, right now the image is darker on the camera screen than with the older Nikon lens (f/3.5).

Any reason for this or why the Speed booster aperture control is not working with my camera?

Thanks,

- Erin

I have the same setup.. I had to take the lens and mount it to a Nikon camera first.. then i open the lens up to 1.8 while it was mounted on the Nikon. then i took it off of the Nikon and mounted it to bmpcc .. So basically i am leaving it wide open at 1.8 and then i will adjust with my speedbooster on bmpcc. if that makes sense ...

You need to mount the lens on the Speed Booster, with the lens set at f/22 and set the Speed Booster per the adaptwr's instructions, which is at "8. On the adapter's scale. When you open the iris ring on the Speed Booster to "F", it should open up the Lens to 1.8, or it's ax f/stop.

Just to be sure, you don't have any filters screwed onto the Sigma do you?

Hi everyone - thanks so much for your responses! I hadn't checked these forums since TIFF started (and I didn't have time to play around with the camera) and I just remembered I had posted here now.

I tried to follow your instructions, however I still can't get it to work - perhaps I am doing something wrong? I'll try mounting the lens on a Nikon and see if that sorts the issue. I will post once I get it resolved and what worked for me.

Also, there is no filter that could be affecting it.

Thanks again,

- Erin

This is crazy, but I found out what was wrong with my lens! I was at a camera show today asking the people at Sigma and they didn't know what was wrong, but showed me how the lenses with Nikon mounts have a mechanical aperture control that operates on a spring and is defaulted in a closed position. I am new to using lenses like this, so wasn't aware of it (I know, crazy).

Anyways, at home I checked the speed booster. Moving the aperture control dial with no lens on, I could see the speed booster had a similar thing that moves back and forth. Obviously, it has to be in the right spot to hit the one on the lens. I tested my lens, it still didn't work. Then I marked how far I had the lens screwed on (matching the words). Taking the lens off, I held it just in front of the speed booster in the same position, and noticed the two little aperture parts that should push each other were about a centimetre (0.39") off.

Turns out, I wasn't screwing the lens on anywhere near tight enough to the speed booster. I screwed it on again, pushing it hard (and feeling like it was forcing) the extra distance. Low and behold, the lens now works. And I feel really silly for not realizing this before (especially now realizing that when screwed on correctly, two obvious white dots line up). I think I was just afraid of breaking the lens or speed booster by screwing it on too tight, since it had already felt like it had 'clicked' into place, when clearly it hadn't.

Don't know if this will solve anyone else's issue, but it was strangely simple, and you won't believe how relieving for me to finally get this to work.

Thanks again for everyone's help!

Glad you got it sorted. Be sure the Speed Booster is set to "8" when taking lens off and on, this will make sure the two tabs line up correctly.