Bogin Bob Loc: Tampa Bay, Florida

I shoot low-light exposure bracketed (3 photos) at ISO 80, f/2.0 and -2/0/+2 bracket. I merge images in either easyHDR or Photomatix.
Interesting observation - Noise (observable) in only one of three images. The affected image (1 of 3) is the one that has the lowest shutter speed in all situations.

Questions:
1. Why? (sorry a very open question)
2. Is it possible to be getting noise from the sensor heating slightly due to a longer duration that the other two exposures?
3. Should I do some noise reduction > sync/save on the affected image > then merge/create the HDR tiff?

Thanks, Bob
Shooting LX-5, on a tripod
Doing a test with another LX-5 and a Nikon (same settings) to see if the sensor itself may be the issue

djtravels Loc: Georgia boy now

I can attempt to answer a part of the problem. From experience, I think it's better to remove the noise from any shot before you merge with Photomatix. I've done 3 shot HDR in low light, knowing noise would be a problem. Tried removing the noise after merging, and it was far less satisfactory than doing it before. Heat sounds like a possibility, but does the sensor hear up that fast? Don't know. djt

jackm1943 Loc: Omaha, Nebraska

It wouldn't be surprising to see noise in the -2, or lowest, exposure. But wouldn't the HDR software ignore the parts of that image that are under exposed and noisy?

twowindsbear

Low light + ISO 80 + 2stops under exposure = underexposed & noisey image

That's my WAG