We were both shooting our Canon 10-22 lenses at night, getting some long bulb exposures of starfields and such.
Here's the thing. All his shots at the same settings blew mine away. Better color, better contrast, sharper. I just had my sensor cleaned, so I know that has nothing to do with it. I think my 10-22 might be off, I need to do a focus test this week. But damn. I didn't expect that big of a difference. Almost everything I shot was fuzzy. THe shots that turned out just didn't seem as nice. And to top it off, on a 20-30 min bulb exposure to get good star motion, his processed in 10 seconds. Mine was working for almost 20 MINUTES.
Obviously, I need to get my camera looked at, it has 9000 actuations. I will definitely be checking my lenses. But that 7D is starting to look really good.....
That 7D is looking better and better....
It also sounds as if you had Auto Focus doing the work. In the 40D you need to attach to a laptop, focus with live view (if you do stars).
The noise reduction you had on will affect the quality and even soften the picture. This will also account for the long transfer durations as explained by someone else.
For stars, the 40D optimum ISO = 800