BMPCC Peaking (focus) leaving residual green pixels

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Craig Seeman

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BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 2:16 am

BMPCC Peaking (focus) leaving residual green pixels.

I'm seeing green pixels that seem stuck when peaking is on. They go away when I turn off peaking though so it's not burned into the LCD.

Steps to reproduce.
Turn on peaking
Close down to f22 for example (makes them more obvious) and green pixels are visible and stuck on the LCD.
Turn off peaking and the green pixels go away.

Anyone else notice this when trying the above?
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Craig Seeman

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 2:34 am

Peaking Green Pixels f22 lens cap on
taken with webcam.

PeakingGreenPixels.jpg
Peaking Green Pixels f22 lens cap on
PeakingGreenPixels.jpg (339.92 KiB) Viewed 2230 times
Last edited by Craig Seeman on Mon Oct 07, 2013 2:39 am, edited 1 time in total.
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Craig Seeman

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 2:35 am

Peaking off f22 lens cap on.
Taken with webcam

PeakingOffClean.jpg
Peaking off f22 lens cap on
PeakingOffClean.jpg (333.21 KiB) Viewed 2228 times
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Craig Seeman

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 12:55 pm

Bump.

Nobody one way or another?
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AdrianSierkowski

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 1:26 pm

I noticed that briefly when shooting at 1600 for a test. However dropping down to 800 and it went away. As peaking is based on contrast, perhaps it is getting confused by the inherent noise of the sensor? I also think my pixel was in a similar location so could even be a slight coding error. If it is not on the recorded footage, and does not spread I wouldn't sweat it. I recall a similar issue on my EX1 when shooting with certain shutter angles.
Adrian Sierkowski
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Craig Seeman

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 1:51 pm

Thanks Adrian,
I'm seeing it at ASA 800. It's only visible when the lens is stopped way down. I don't seem to see it a f5.6 for example.
It does seem to be only cosmetic.
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AdrianSierkowski

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 2:08 pm

Peaking is kind of a "dumb" function if I understand it correctly. It just displays a green pixel where it detects x amount of contrast between two pixels, as such, things like noise an probably fool it-- especially when it doesn't have anything else to go on. The camera, afterall, doesn't know what it's really looking at. It just says, oh, this is a super low contrast scene (black) but there is a y% difference between these two pixels, so I suppose this is a thing which is in focus.

Unless it gets worse-- e.g. you see it all over the images in the real world to the point of making it useless-- or you see it recorded in footage, keep calm and keep shooting ;)
Adrian Sierkowski
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Craig Seeman

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 2:42 pm

Given that I'm stopped down and, in the above case, lens cap on and the pixels don't move, it would make sense that it's sensor noise.
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Craig Seeman

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Re: BMPCC Peaking (focus) leaving residual green pixels

PostMon Oct 07, 2013 5:41 pm

Confirmed in a test by turning on peaking at f3.5 instead of f22. Put on lens cap and there are no green pixels. Stopped down all the way is just confusing the peaking.

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