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Wheatfield · 08-27-2008, 07:11 PM

Originally Posted by jmbower

I'm not sure exactly what I'm doing wrong, and haven't had a lot of time to play around. I was hoping someone might be able to diagnose the issue before I drove myself nuts trying to figure it out

Here's the deal: I have a K100d (old version) and have been happily clicking away on it without any major issues. However, I haven't tried to do a lot of longer exposures...just mostly here and there for flowing water, etc.

I was out at an observatory, and decided I'd give star trails a shot....just a brief one, not the hours of exposure to get full circles, etc. After a 30 second exposure on a tripod (with SR turned off) I got what looked like a dim picture covered in red static. I didn't think much of it at the time....but the picture at the top is from last night...I tried to do a long exposure to capture the trails of bats coming ot from under a bridge. Same deal, lots of red/purple static.

Another example:

what am I doing wrong? Any hints/tips/general rules for long exposures?

Thanks!

p.s. (sorry no exif data, I'm not at home, so had to convert the raw files with picasa)

You are doing nothing wrong. That is sensor noise caused by heat build up during the long exposure.
A friend of mine calls it a fatal problem, as he does long exposures a lot.

08-27-2008, 07:11 PM	#3
Wheatfield Pentaxian Join Date: Apr 2008 Location: The wheatfields of Canada Gallery Photos: 0 Posts: 1,257	Originally Posted by jmbower I'm not sure exactly what I'm doing wrong, and haven't had a lot of time to play around. I was hoping someone might be able to diagnose the issue before I drove myself nuts trying to figure it out Here's the deal: I have a K100d (old version) and have been happily clicking away on it without any major issues. However, I haven't tried to do a lot of longer exposures...just mostly here and there for flowing water, etc. I was out at an observatory, and decided I'd give star trails a shot....just a brief one, not the hours of exposure to get full circles, etc. After a 30 second exposure on a tripod (with SR turned off) I got what looked like a dim picture covered in red static. I didn't think much of it at the time....but the picture at the top is from last night...I tried to do a long exposure to capture the trails of bats coming ot from under a bridge. Same deal, lots of red/purple static. Another example: what am I doing wrong? Any hints/tips/general rules for long exposures? Thanks! p.s. (sorry no exif data, I'm not at home, so had to convert the raw files with picasa) You are doing nothing wrong. That is sensor noise caused by heat build up during the long exposure. A friend of mine calls it a fatal problem, as he does long exposures a lot.