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Old 16-05-2011, 08:27 AM
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jjjnettie (Jeanette)
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Canon 550D and 20D noise comparison

These are the autosave files out of DSS. Both are of approx the same exposure time, been cropped and the same amount of levels applied.
I've added a pic from an unmodded 20d now.
All were taken through the same scope.
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Click for full-size image (m83-20d-modded.jpg)
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Click for full-size image (m83-550d.jpg)
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Click for full-size image (m83-20d.jpg)
159.3 KB159 views

Last edited by jjjnettie; 16-05-2011 at 08:48 AM.
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  #2  
Old 16-05-2011, 08:30 AM
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iceman (Mike)
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Interesting!

The 550D looks noiser, but hard to really tell with the modded 20D and the difference in image scale.

In fact it could be the image scale that contributes - the 550D has more pixels on the same size sensor = more noise.
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Old 16-05-2011, 08:40 AM
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jjjnettie (Jeanette)
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And there is no way, without clipping the image badly, to remove the noise.
I'd bought the 550 as a deep sky imaging camera.
I'm highly disappointed.

But it's still great for lunar, solar and terrestrial work.
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Old 16-05-2011, 11:30 AM
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Ewwww glad i didn't get one 20D...... mmmmmm .... smoooth
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Old 18-05-2011, 10:49 AM
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noise or no noise, a DSLR isn't a deep sky camera and as such suffers from thermal noise as you well know. The other thing is the 500 series is only one step up from the 1000 series of canon plainly put they are virtually the bottom of canons range the 5 series is phenomenally better in regards to noise as its the top of the range camera. though if you where purchasing a 5d to do the job of a cooled astro ccd? it wont come close. that is my thoughts on the situation.

brendan
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Old 22-05-2011, 07:36 AM
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I agree with Brendan...
For dedicated astro-work, however, I want to go with cooled, BW CCD (don't forget, it will be up to 3x more sensitive - 3x less noise compared to bayer matrix sensors used in DSL's).
In the meantime, my 400D is good enough..
I can even do some realy serious work on brighter objects like photometry od variables and SN with 400D.. (I am sure 500D will be OK as well for this), but I still think that the dedicated astrocamera is better solution - I will be able to go much deeper.

Last edited by bojan; 24-05-2011 at 06:03 PM.
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Old 24-05-2011, 05:01 PM
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what is the exposure of the 550D image? Ive never seen noise like that before from my 7D - that is an 18mp sensor...
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Old 26-05-2011, 06:04 AM
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Modded 550D

Yikes! I've recently purchased a 550D and just had it modded by Peter Tan in HK. I haven't tried it yet but after seeing Jinette's image, I am horrified. Now the IR block filter is removed, I guess I can't even use it for lunar or terrestrial work. Oh woe is me! Can anyone help please? I only did it because of Live View.
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Old 26-05-2011, 06:34 AM
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Hi Mel, you can still use a modded camera for normal use if you create a custom white balance. You just won't be able to use any of the automated functions, just the programmable ones.
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Old 26-05-2011, 07:19 AM
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If you cool it (search this forum for Bert's aka Avandonk's styrofoam fridge - it's not expensive exercise at all) you may still be able to get decent results.
And, perhaps Jeanette's specimen is really bad... not very likely but still it's worth the investigation, taking into account the money you already spent on this...
And, the fridge will help to significantly reduce the noise of any other camera as well.

see here:
http://www.iceinspace.com.au/forum/s...=camera+fridge

Last edited by bojan; 26-05-2011 at 08:01 AM.
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Old 26-05-2011, 08:44 AM
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I'm yet to try mine on a cold night. So fingers crossed we'll have better luck.
My next experiment is to extend the interval between shots. Give that sensor a chance to cool right down before the next one.
Looking forward to seeing good results.
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Old 26-05-2011, 08:23 PM
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I learned a heck of a lot playing with my 450D for 18months. Guiding, balance, how to find and frame objects , focusing, processing, really good swear words. I still think the humble DSLR is a good entry point for many people who may not be obsessive compulsive enough to continue with AP.
(twitch, twitch, head-shake, twitch.... )

Disappointing to see you're still suffering with the 550 though Jeanette. Might be time to go 2nd hand QHY8 if don't want to go the whole mono CCD/Filterwheel route? If its not cold enough at astrofest for the 550 you'll know its got problems...!
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Old 28-05-2011, 02:04 AM
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I used to use the 40d, it got alot better when the ambient temp dropped below 10 degrees. down to 5 and it started to kinda work like a deep sky camera. At the end of the day I knew what my condition required and i couldn't be happier to have spend the coin on a decent mono cooled CCD!

Good luck J
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Old 06-06-2011, 11:49 PM
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I managed to purchase a new EOS XSi (450D) from the US at a very reasonable price, so I'll have that modded instead and the 550D restored to normal. That will make a handy 2nd body for my 50D.
All very expensive, but should be a good outcome. Many thanks to jjjnettie for sending me in the right direction!
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