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Topics - David Goldwasser

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#1
Post-processing Workflow / Does anyone have workflow for dark frame subtraction for video
May 27, 2015, 08:28:59 PM
My use case for this is for FPS override video. As shown on this post http://www.magiclantern.fm/forum/index.php?topic=15205.0 I have bad pixels that are very evident when using FPS, in particular if I'm in the 0.2 to 1.0 FPS range. If I were shooting with intervalometer I would jsut use camera's (550d) built in dark frame subtraction or post process the photos. Since I'm shooting videos for FPS Override I'd like to avoid converting to still and then back to video.

It would be really great if there was a way ML could do this as it captures the video, but nto sure that is possible. I can try opening up aperature (using ND filter) and then maybe shooting faster FSP, and then speeding up in post processing?
#2
Share Your Videos / Initial ML testing intervalometer vs. FPS override
May 20, 2015, 08:48:41 AM
I just traded in my old 20D for a used T2i so I can use magic lantern. Did some initial testing to compare time lapse with intervalometer vs. FPS override.

Here is a link time lapse video made with intervalometer. Camera in AV mode aperture around 1.8 with 50mm lens shots every 5 minutes


Below are two screenshots from similar setup but using FPS override with 0.2 FPS. For both of these I used an power connector vs. battery which dealt with heat. The FPS still got hotter with sensor stabilizing around 26C. The noise got worse as it got hotter, and I assume to prevent overexposure it was closing the aperture which made any sensor issues seem worse. I wish I could resolve this, I suppose I could post process to remove the noise, but that isn't ideal. Eventually I'll get a new body but for now I've upgrade from my 10 year old 20d to a used t2i.

Below is image capture from FPS override video early in the sequence


This image is later in the FPS sequence


For reference this last one is photo taken with the camera in photo mode with similar setup



Here are two additional tests with my camera of sky time lapse.

This one had camera in program and shot every 1 minute (no ramping setup)


This one had ramping setup. At night got >30sec shutters and high iso. Soon I'll try to do some outside testing without glass and see how I can do with stars.
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