Quote:
Originally Posted by Asterix2020
Another thing I have been doing is using dcraw to convert my RAWs to TIFFs before stacking in DSS as recommended by Ivo (thanks Ivo). This has increased the dynamic range in the final processed image.
I've been confused about bias and dark flats. Some people saw that Canon dark frames already have a bias in them so bias frames are not needed. Some say don't use dark flats and bias as the read? (not sure if read noise is the correct term) noise is subtracted twice, so only use one or the other. But if dark frames already have the bias, would using dark flats subtract the read noise twice? And if my flats are in the 1/80 second range, would dark flats be needed?
Also, is there any reason not to use lots of dark frames if you have them? I set the camera up last night and could use 100 temperature matched dark frames for an image. Since I have them, is then any harm in using them? I understand there may not be a lot of extra improvement over say 50 frames, but would it make the image worse?
I'm using a CDS-600D (cooled, modded Canon 600D).
Thanks for starting this, I think I'm going to learn a lot.
|
To answer briefly Paul. I like the idea of dcraw conversion applying optimal options. I read that post. Secondly, if you adhere to bias in the dark to calibrate your lights and don't use bias at all, there are no double subtraction issues. As to flats, calibrate them separately with a bias or as in my previous post, below. This might mean double handling to produce master dark and master flat frames, but it's worth the effort.
EDIT. Lots of dark frames produces a better mean, afaik. EDIT: See up thread.