My trouble is that when I shoot lets say a shot with 2 mins exposure, then after shooting that "wait" screen is ALSO of 2 mins! So that is 4 mins a shot! Can I get rid of it?!
I only need RAWs, but I was told I cannot get rid of JPGs, but can I?
but unfortunately my cam only shoots it like 0 +1 -1 +2 -2 +3 -3 +4 -4
This is "dark frame subtraction" done by the canon firmware. On most CHDK ports, you can disable it by setting "Dark Frame Subtraction" to off in the "Enhanced Photo Operations" menu, but quality may suffer unless you do dark frame subtraction on the raw later. Google "dark frame subtraction" to learn more about this process.
You cannot disable jpeg using CHDK. You can set them to small and lowest quality (as you described), but this will likely not improve shooting speed much. On some cameras, using lower resolution jpeg is actually slower than the full resolution L size.
Quotebut unfortunately my cam only shoots it like 0 +1 -1 +2 -2 +3 -3 +4 -4 This is how CHDK built in bracketing works currently. You could write a script to do it the other way.
Quote from: reyalp on 13 / March / 2016, 03:00:57This is "dark frame subtraction" done by the canon firmware. On most CHDK ports, you can disable it by setting "Dark Frame Subtraction" to off in the "Enhanced Photo Operations" menu, but quality may suffer unless you do dark frame subtraction on the raw later. Google "dark frame subtraction" to learn more about this process.Quotebut unfortunately my cam only shoots it like 0 +1 -1 +2 -2 +3 -3 +4 -4 There is a script that manages dark frame subtraction - disabling it for each shot but occasionally collecting a reference dark frame for use in post processing. It would not be hard to modify it to shoot in your desired sequence with a reference dark frame taken at the beginning and end of the sequence.link > Meteor Intervalometer with Dark Frame Management
Does CHDK apply "Dark Frame Subtraction" in its RAW?! I can see a lot of coloured noise (red, green, blue pixels) in the RAW files, but the JPGs are clean. So until now I've been using Dark Frame Subtraction and wasn't even getting any benefit from it, since I only use RAW!
I've read that the Dark Frame has to be of the same settings (ISO, Ap, Tv) for ALL the frames?!
For some reason Camera RAW processes the RAW files and it kills the noise, but along with that softens and smudges the frame (like all processed images look). The reason to shoot RAW is to circumvent this "processing"
Dark frame subtraction is done by the Canon firmware. It is done on the raw data, so it affects both CHDK raw and Canon jpeg.Dark frame subtraction only deals with with things dark current, hot pixels, amp glow. The noise you see in the raw is from other sources like shot noise. The canon firmware does noise reduction when it creates the jpeg. You should be able to do similar in your raw software.
The shutter speed and ISO should be the same as the shot you are subtracting from. It's also best if the sensor is at the same temperature. Av shouldn't matter. With CHDK raw, you might need different dark frames for different zoom levels, because some cameras do vignette correction in a way that affects raw.
Some software (raw therapee, for example) lets you keep a collection of dark frames and picks the closest matching Tv/ISO.
Sounds like it is doing noise reduction for you. There is always a trade off between how much detail you keep and how much noise you see. Raw doesn't change that, it just lets you decide where to make the trade.
I'm NOT sure if it is doing Dark Frame Subtraction (DFS) on my RAWs as my RAWs have a lot of coloured noise (not 'normal' noise, but the coloured pixels of dark current, hot pixels, amp glow etc)
This DFS is causing me a lot of problems! I'm now contemplating of getting rid of it completely and see if skipping it makes much of a difference.
Why is it doing that noise reduction, when I'm NOT telling it to?!
I tried RAW Therapee and even it processes the images by default!
I need something that DOESN'T process the image, just convert it from RAW to TIFF, without any loss in data.
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