Focus Issue

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Christos Pantolmos

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Focus Issue

PostWed May 24, 2023 5:32 pm

Greetings. In a recent shoot we had with some colleagues we used a BMPCC4K as the main camera. Every function was fine, but when we played back the clips to see what we had shot, when we returned to the recording menu the focus had been lost. Is it normal? How do we handle this? Thanks.
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Uli Plank

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Re: Focus Issue

PostThu May 25, 2023 1:51 am

Do you mean the focus position on a fly-by-wire lens?
Get mechanical lenses and a mechanical focus wheel.
No, an iGPU is not enough, and you can't use HEVC 10 bit 4:2:2 in the free version.

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Christos Pantolmos

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Re: Focus Issue

PostThu May 25, 2023 12:35 pm

No, we were using a Panasonic Lumix Vario 12-35mm II. I think it's mechanical. If I didn't explain it correctly, I mean that we would focus let's say at 12m from the camera, and when we exited playback it would focus automatically to 0.5m. Not exact numbers but to give you an idea.
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Uli Plank

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Re: Focus Issue

PostFri May 26, 2023 4:02 pm

Then it's fly-by-wire. Mechanical lenses don't move on their own.
No, an iGPU is not enough, and you can't use HEVC 10 bit 4:2:2 in the free version.

Studio 18.6.5, MacOS 13.6.5
MacBook M1 Pro, 16 GPU cores, 32 GB RAM and iPhone 15 Pro
Speed Editor, UltraStudio Monitor 3G, iMac 2017, eGPU
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Christos Pantolmos

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Re: Focus Issue

PostFri May 26, 2023 8:44 pm

Yes you are right. It is fly-by-wire. THANK you so much. It really bogged me down. I couldn't get my head around it. Appreciate it a lot.
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Robert Niessner

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Re: Focus Issue

PostSun May 28, 2023 10:55 am

When go into Playback mode and back to Rec mode the camera does a short soft reboot, resetting also the lens mount. So the lens electronic does a reset too and seems to put the focus somewhere else, as it is relative and not reliably repeatable.

I had a similar issue with my UM46K and a Canon EF 100-400 mm which would re-focus after soft reboot even with AF switched off.
Saying "Thx for help!" is not a crime.
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