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Color Snow issue on Epic footage??

James Drake

James Drake

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Here are the parameters:
800 ISO, 1 frame per second, HDRx, 5k 2.4:1, RedCode 5:1
A black shading was not done prior to the shoot, we have not seen this issue in any of our other footage.

We're thinking it's the 1FPS thing, as we shot another shot at 12fps and 24fps and did not see the problem.

Almost looks ok in the wide...
colorsnow2.jpg


But looking closer,
colorsnow1.jpg


Anybody else experience the issue?
 
This is why you have to do the black shading in the frame rate you are shooting. Mainly for anything under 12fps. I've done some tests using the 1fps function and it looks great if you black shade it in that mode. So next time do the black shade calibration before you start shooting at 1fps and you'll get nice clean footage.
 
Joe Pontecorvo said:
Can I ask how you are shooting 1 fps on your Epic. My lowest frame rate is 12 fps.
Click to expand...



press and hold the FPS setting and you can input your desired number down to 1 :-)
 
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In RED, doing black shading does not help to eliminate these color hot pixels. We have to do post work to remove the entire hot pixels, not hard but extra steps to do.

Im not sure if EPIC will cast away this issue by doing black shading....

Rivai
 
RivaiC said:
In RED, doing black shading does not help to eliminate these color hot pixels. We have to do post work to remove the entire hot pixels, not hard but extra steps to do.

Im not sure if EPIC will cast away this issue by doing black shading....

Rivai
Click to expand...

I've specifically tested and seen hot pixels like this properly taken care of by the black shading on EPIC. The only down side is that black shading can be a very lengthy process, not suitable for making an in-the-field choice on a whim necessarily.
 
Would be great if we had a possibility to store different shading settings, instead of doing them again every time.
Not sure if this will someday be possible, but i´d really like that :)
 
Would be a good idea to have black shading stored in the camera for different settings as others have said. But what would be nice is to have Epic be smart enough to do one black shade calibration for two settings. So you do one calibration and Epic will save the info for 24fps and for slower shutter speeds that go along with slow frame rates. It would be much faster than black shading out in the field and make the camera much more versatile for shooting all different types of situations.
 
RivaiC said:
Im not sure if EPIC will cast away this issue by doing black shading....

Rivai
Click to expand...

it does a pretty good job....there's been a whole thread on this subject, in which Deanan, I think, gave pretty good instructions on shooting 1 fps.

I've timed it, and black shading at these settings takes around 11 minutes - longer than the RED ONE, almost so yes, it can be a bit of a time suck...especially if, for any reason it fails (light leaks can cause this...best to shut down and start over, if that happens, it will usually not self-adjust, and suddenly you can be half an hour into failed black shading calibrations, if you get stubborn about it).
 
Andrew Walker said:
Would be a good idea to have black shading stored in the camera for different settings as others have said. But what would be nice is to have Epic be smart enough to do one black shade calibration for two settings. So you do one calibration and Epic will save the info for 24fps and for slower shutter speeds that go along with slow frame rates. It would be much faster than black shading out in the field and make the camera much more versatile for shooting all different types of situations.
Click to expand...

Black shading can change over time (sensor age) or with different temperature conditions. So storing shading values indefinitely would not be good. I do think the camera should be allowed to save a few different shading calibratons that it can call from, not just one. And then pop up a notice if one is out of date or seems to not match the current temperature or mode chosen for shooting.

I've got the best result for longer exposures like this by doing a black-shade for the longest possible exposure time -- 1 second. So set your frame rate to 1fps and a 360 or 1fps shutter before doing the calibration. You can always dial back the shutter speed from there when actually shooting.

The hot pixel noise can be cleared up in post with some decent de-noise techniques. It's actually easier to clean up than most of your typical noise as it's often pixels stuck full bright, or close, and with a single R, G or B value.
 
Well, not too easy to clean up, since it's fixed pattern noise. As it doesn't change from frame to frame, temporal denoisers (which preserve more detail) don't see it.
 
One thing to note, it's best to stay in the original resolution when doing this denoise work before you do any scaling down, it produces better result.

Uli : Try use median..typical denoise doesnt work very well
 
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