Quote:
Originally Posted by bmitchell82
with what your saying gary theres a difference in the cameras by quite a fair amount, i read somewhere for instance the 350d and the 40d that the 350d's iso 800 was the 40d's iso 400.
Ide hardly belive that canon would go so far backwards when it came to noise and amplification of their sensors, irrispective of this problem temperature is 90% the cause of such noise, if you turn a dedicated astro ccd on and don't use tec, it will most likely look similar to the noise profiles you hvae shown.
My M42 shot that recently gained 1st place in astronomy WA's Astrofest had NO reduction shots aka no flats, no bias, no darks no nothings. yet its silky smooth without any noise ninja, noise works help.
what was the good news for that. Temperature blimy it was close to zero degrees. From this night on darks only reduce so much noise, but as bert has pointed out, it leaves holes in your fine faint data basically killing the image. so if you want limited/no noise you need to cool her down!
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Brendan, yes I have heard that the 40D would be similar at iso 200 as to the 350D at iso 800. I don`t know if that`s to do with 12bit as apposed to the 40D`s 14 bit depth and would that infact make a impact on the thermal noise using the lower iso?
If someone can explain this I would love to know...
When I mod the 40D I shall give both camera`s a better comparison.
Yes, if you can keep it cool it makes so much difference! Even my old 300D gave terrific results when it was -3 deg outside. Stack 5 or so it would be silky smooth.
But saying that like Humayun mentions if you calibrate the darks/flats/bias you can get pretty close. But I have noticed when doing stacks of images during warm periods I often get that streaky look to the image when stretched but never when it`s real cold.
Robbie, why not give Deepskystacker a go, it`s free and it does a fine job once you get it going.
cheers Gary
