20d sensor

Hey guys, i had a question about my 20d. I've heard that the 20d's were the first consumer camera built with a sensor less susceptible to digital noise. I was wondering how much this applies to night shooting. I'd like to start doing more night shooting and was wondering how long i could expose for without getting lots of noise.
thanks
andrew

hm, what kind of night shooting are you talking about? cause even on my digital rebel, i could expose for up to 30 seconds at night (and im sure it could have gone longer) with no noise at all. and it would come out crystal clear.

I would like to try some long nigh exposure possible up to five minutes or more.

well the statement isnt entirely correct, because every sensor as they develop technology becomes less and less susceptable to noise, with some exceptions. full frame cameras have less noise as well. One problem that you may run into/want to check out before you try 5 minutes is the risk of overheating the CMOS sensor. do some research before you try a 5 minute exposure. it won't be as much the noise you will have to worry about as the heat.

What will really be a problem is the battery drain.
The shutter has to be electromagnetically held open.
So if you think how many 1/100 second exposures you could take, vs a 5 minute exposure ...
I would make sure to have spare batteries.

Heat in the sensor will appear as a slight glow if you convert to B&W.
Often seen near the amplifiers on the edge of a CCD sensor.
But on CMOS there is one amplifier per pixel, so it's very different.

http://www.astrosurf.com/buil/20d/20dvs10d.htm
Although about astrophotogrraphy performance, they use 5 mminute test exposures in the section on thermal noise.
Also under amplifier glow, you see the 20D has far less becuase of the distributed amplifiers, each of which has programmable gain.

I don't think 5 minute exposures are going to be a problem.