Marvellous what a difference temperature makes

[tornado33]

Was looking at some past images Ive done, and decided to check darks I did in summer and compare to ones I did 2 nights back when it was very chilly.
Both are full res crops from same part of image.
One was at an ambient temp or around 20 degrees, the other at 8 degrees. Look at the difference in noise. Bert has the right idia, making a fridge to go round the camera. DSLR's dont need to be cooled to 30 below. If this dark is so dark at 8 degrees, at around zero thermal noise would be almost non existant.
Scott

[jjjnettie]

:eyepop: That's incredible!

[leon]

Yea Scott that is right, I love it when it is about zero, and the frost is on the ground, best time for imaging, nice comparision. ;)

Leon :thumbsup:

[rat156]

I think that you'll find if you stretch the cold one, most of the dark current is still there.

Cheers
Stuart

[Bassnut]

Yeah, posting a dark comparison as an 8 bit JPEG? :rofl::rofl:, nice try ;)

[Tandum]

I went back and checked a pair of mine, 12/08 and 7/09 ... same iso/same time..no difference I can see. They are a lot noisier than yours :)

[cfranks]

I bought one of those Car Cooler thingies from Tandy. Peltier cooler for $16.00 and left my 40D in it all day. It got down to about 3deg but the Darks were just as noisy as the room temp ones so I ordered a QSI 540wsg!

[Lester]

Nice comparison Scott. What was the exposure time for those darks?

Some of the Canon camera models produce more noise than others too.

[Geoff45]

Good choice! Great camera.

[Geoff45]

Here's the 8 deg dark with a bit of a stretch. A cooler one would show less dark current.
Geoff

[bmitchell82]

hehehe :) the CON of a dslr :) lucky we ues it for "dark subtraction only "

[tornado33]

Both darks were 10 mins.
They say each 6 degree drop in temp is 1/2 the dark current I think? The darks werent stretched or adjusted in any way, just opened with canon's software abd turned to jpeg