Aperture trouble with sigma 18-35 on Pocket 6K G2

I have the following problem with the Pocket 6K G2 camera when I use the camera with the Sigma 18-35 lens:
When I set an aperture value between 2.1 -2.7 , then go to playback mode and then back to shooting mode, the aperture value (numberon display) is the correct one, but actually the aperture has closed further and I get significantly less light on the sensor. The only way to avoid the problem is to close the aperture completely once after leaving playback mode and then open it again to the intended value.

Does anyone else have the same problem? Can you reconstruct this problem or do you have a solution? I suspect that it is related to the update to firmware 8.1.

I look forward to your feedback!

You have auto mode on the lens on?

I had numerous issues with the Sigma 18-35 and 50-100 over the years on my Blackmagic Cameras. But also the Canon 7D. I'd lose aperture control every once in a while with the BMD Cams. But the Canon 7D also and on top it would no longer communicate with the camera for focus indicators in the Viewfinder. Overall, I think the EF electronic connectors on the Sigma lenses are not the best. However, the Sigma DG DN E-Mounts have been amazing on my Sony.

One of the major reasons I want a physical Iris Ring on the lens is so that I can still opt for manual control. I have that with my DZOFilm PL Mount Lenses, but also the Sigma DG DN lenses have it as well. So, if I did lose the electronic communication for whatever reason I could still use full manual aperture on the lens.

No matter, I'm never going back to EF. I'm staying PL or LPL for the future for video. And, for stills I'm investing in Sony for now, but would go back to Canon with RF.

There may be a firmware available for the sigma 18.35. I downgraded back to 7.9, but I think you can stop down fully and then open up fully to recover the full range of the aperture. I know I have a firmware upgrade available for my 18-35, I don't have a dock to update it currently. When I do I will try the latest firmware again to see if there are any improvements.

There may be a firmware available for the sigma 18.35. I downgraded back to 7.9, but I think you can stop down fully and then open up fully to recover the full range of the aperture. I know I have a firmware upgrade available for my 18-35, I don't have a dock to update it currently. When I do I will try the latest firmware again to see if there are any improvements.

Right, well I sold mine. Thrilled to get rid of it. But the firmware was most up to date on the lens even when I had the issues. Especially on the Canon camera. I really started to say that the lenses were not reliable for stills due to the issue of focus indication not working often.

The thing I love about switching to Mirrorless for stills is that I can use the EVF and zoom in to focus with it. Far better than the optical viewfinders on DSLRs.

Either way, I was never a fan of the 18-35 like so many.

But the firmware was most up to date on the lens even when I had the issues. Especially on the Canon camera. I really started to say that the lenses were not reliable for stills due to the issue of focus indication not working often

Did you have issues with the Blackmagic when the Sigma was on latest firmware? Or was it mostly Canon issue using for stills. This is nice information and all, but the OP doesn't have a canon camera and isn't using it for stills.

But the firmware was most up to date on the lens even when I had the issues. Especially on the Canon camera. I really started to say that the lenses were not reliable for stills due to the issue of focus indication not working often

Did you have issues with the Blackmagic when the Sigma was on latest firmware? Or was it mostly Canon issue using for stills. This is nice information and all, but the OP doesn't have a canon camera and isn't using it for stills.

When it came to focus no issues on the BMD cameras because I could enable focus peaking. I only really ever lost aperture control with the Sigma 50-100 every once in a while. Maybe it was the lenses weight because I had the same issue with the Canon 70-200 last year on a shoot. Granted, that 70-200 was one where the person who owned it knew it had issues with the lens data contacts and it had issues on his C300ii. So...

The summary is that I really believe that all lenses should have a manual option with a physical iris ring. Not just cinema lenses, but also still lenses. As long as you can bypass the camera control via lens data connectors then you should be fine with shooting.

You have auto mode on the lens on?

No auto mode activ. Thx