Lines in Pocket 4K footage?

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stencil

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Lines in Pocket 4K footage?

PostThu Aug 01, 2019 3:26 pm

Within the past week to so, my Gen 1 Pocket 4K has developed two faint lines in the image. The lines are on roughly the left 1/3 and right 1/4. They show both onscreen while recording and in recorded footage viewed on a computer.

The lines are most visible in underexposed areas and only manifest in the “low gain” band of the sensor, from ISO 100-1000, and disappear at 1250 and beyond. The areas on either side of these lines have very slightly different exposure and tint, and this shows in false color as well. They are entirely static, and not related to the lines that can appear in deeply underexposed noise. The lines are faintly visible even without a lens attached and there is nothing obstructing or otherwise dirtying the sensor.

I’ve tried pixel remapping/black shading, factory resets, and firmware upgrade/downgrades. Nothing seems to rid them except shooting in the high ISO band.

Any advice?
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rick.lang

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Lines in Pocket 4K footage?

PostThu Aug 01, 2019 5:14 pm

Could you post some pics that are of a normal subject, not False Colour? Not seeing them in the 3200 ISO band indicates an underexposed frame, but you should be seeing the purple Colour in False Colour and you only show Blue and Dark Grey.


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stencil

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Re: Lines in Pocket 4K footage?

PostThu Aug 01, 2019 6:07 pm

I’ll upload a non false color image later, but the lines are present at all ISO values below 1250, but disappear after switching to the high ISO band, even when jumping from 1000 to 1250 on a normally exposed scene. They are unfortunately difficult to capture because they’re most visible against motion rather than in stills.
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stencil

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Re: Lines in Pocket 4K footage?

PostThu Aug 01, 2019 10:08 pm

I've increased the contrast on this image to better show the rightmost line, but the wall was exposed at just under middle gray to exacerbate the issue. Everything right of the line is slightly darker.
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rick.lang

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Lines in Pocket 4K footage?

PostThu Aug 01, 2019 10:36 pm

That’s not a line, just the border of that strip that is darker than the adjacent area to its left. Looks like it is related to a poor exposure, but I don’t recall seeing anything like that on my purposefully underexposed tests.

I’d still contact BMD Support and send them a variety of samples with and without those dark strips at ISO 400 and ISO 3200. I would recommend you don’t send them False Colour stuff, send real images.


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Bunk Timmer

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Re: Lines in Pocket 4K footage?

PostFri Aug 02, 2019 7:01 am

In Photoshop I could make the line on the left visible as well. Eventhough it was just a jpg.
I think it is a reason to get it send back.

…However, they are now faint and hardly noticable. You could gamble that it won’t get any worse …once you sent it in you will lose the stripes, but with it a cDNG capable P4K as well.
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Ulysses Paiva

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Re: Lines in Pocket 4K footage?

PostFri Aug 02, 2019 1:12 pm

Isnt that from the lighting itself? I mean, from what looks like light coming from a window?
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stencil

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Re: Lines in Pocket 4K footage?

PostFri Aug 02, 2019 1:30 pm

The strip/lines are not from the window lighting, unfortunately. The strips are visible on the back screen and are completely static. They don’t show that easily in stills, but in lining up a shot, panning, etc., they are much more noticeable. The image looks like it is divided up into three strips, with the darkest one on the right and the lightest on the left. This holds true for all exposures and ISO values in the low gain band. They disappear as soon as the high ISO band is engaged.
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LJames

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Re: Lines in Pocket 4K footage?

PostThu Nov 25, 2021 4:55 pm

I'm experiencing the same issue with my pocket 4k's. These were both bought at the beginning of last year. They're not that old but both of them show this artifact even with no lens or speed boosters or anything attached. It does only show prominently in the shadows. It does not show in the high sensitivity circuit even with the same exposure values. The artifact is more easily identifiable with false color on. I have a video but I can't seem to attach it here but with a little camera movement this line becomes more prominent. There is another line frame left but it is barely detectable. I'm submitting the issue to BMD to see what they recommend to resolve this.

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