Hey Andrew,
The sample images you posted look like fixed pattern noise to me, BMD had similar issues with their 1st 4k camera when I recieved it. Black shading is of course easier for everyone (production and post) when applied in camera but can be done after the fact.
The steps I've used in the past are as follows:
- Record about 2-3 minutes with the port cap on.
- Make sure that you are doing all your math with a linear oetf in the compositing app of your choice or the math just won't work right.
- Average out the dark frames. (eg ADD all frames then DIVIDE by the number of frames)
- SUBTRACT the averaged dark frame from each frame of footage.
It's cumbersome and much better when done in camera, but it is a method of salvaging shots when either a black shade wasn't done or was done incorrectly.
My recollections from working with the Phantom HD Golds of yesteryear was the phantom tech would blackshade everytime we changed frame rate.
Sincerely, Andrew Hunter 1st AC/ Sometimes DP+workflow janitor Toronto, Canada
On Thu, Apr 1, 2021 at 3:29 PM Andrew Boulter < andrew@...> wrote: Thankyou Art,
So my next question is would black shading solve the problem I am seeing, and is that something a firmware update can cure, or not…….?
Andrew
Andrew Boulter Director of Photography UK based but thanks to Covid, currently in Dubai for the foreseeable +447768877686 +971585047839 On 1 Apr 2021, at 20:20, Art Adams < aadams@...> wrote:
Hi Andrew- You’re thinking about black shading, not black balance. Black balance will just make sure black is black. Black shading is about eliminating noise and fixed patterns. -Art | _______________________________________________________ | | ARRI Inc.
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Yes, sorry about the examples, they are not great, here’s one more, I have increased the brightness and raised the shadow areas just to so you can see the pattern. I hasten to add this is only to see the lines, forget the colours etc. One of my thoughts was that its to do with a black balance, which isn’t possible, I then thought perhaps the temperature of the sensor might be an issue, I know when shooting Phantom some techs have told me they want the camera to ‘warm up” My main question is , what is producing the pattern, obviously the sensor, but what part of it and why? UK based but thanks to Covid, currently in Dubai for the foreseeable
On 1 Apr 2021, at 19:25, Colin Elves < colin@...> wrote: I agree 100% with Alister: the frames are too small to judge (😃) but my initial assumption would be that it’s fixed pattern noise. Most cameras address this with a black balance. If that’s not an option here you’ll need to do it in post.
Colin Elves
Director of Photography
Back in Brussels On 1 Apr 2021, at 20:10, Andrew Boulter < andrew@...> wrote: Thanks Alister, seems I forgot to mention one important thing, it was lit with sunlight alone, so its not that. Andrew
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