Nikon D80 amp glow - the saga continues - mainly facts but also some speculation.
In the part one I did not hide my disappointment with the long exposures amp glow on Nikon D80.
After using the camera for over a year, little has changed. Even that Nikon released a firmware update which supposed to improve long exposure noise reduction, the amp glow is clearly visible in long exposures with filtering enabled or not.
I tried the camera with external power and with battery grip. No change. Long exposure noise filtering improves things somewhat but it does not eliminate the ugly, purple glow in the corners. Removal of the amp glow in Post processing proved to be extremely difficult and (in my opinion) not worth the effort since, heavy amp glow kills the detail.
I have tried multiple exposures but, it also proved useless in dealing with the amp glow - the amp glow in shorter exposures maybe very faint and not noticeable in a single exposure but, it accumulates when exposures are stacked and can easily ruin the day...
At the end, I decided that I will try to avoid exposures over 3 minutes long and let the camera do what it does best - take "normal" photographs and for that D80 is a very good camera.
All in all, one may ask a question: "Am I happy with the D80?" To be truthful, the short answer is: Yes! OK, I am anxiously waiting for the release of D300. It has many features that D80 lacks and I could use BUT unless D300 will prove to be good for very long exposures, more than likely, I will stick with the D80 until Nikon releases a camera that is capable of amp glow free exposures of 20+ minutes. Until than, an old Nikkormat and few rolls of Fuji film will be going with me whenever I anticipate taking long exposure shots and I still keep on trying to push D80 right to the limit and beyond.
Nikon D80, Exposure 19 minutes 47 seconds ISO 200, shadows pushed a little in Capture NX,
The incredible orange in the sky overpowering the faint green light of Aurora Borealis thus ruining the shot is courtesy supplied by Nikon D80
Duncan Munro offers the following advise:
The only way to fully remove the amp glow in the D80, is to
use NEF files, turn NR off, and then take your exposure (light frame) and then
do another exposure of the same length, but with the lens capped. You then
subtract your "dark frame" from the "light frame". There is
freeware software that will help you do this, although I think PS can do it as
well. The best freeware software is IRIS, IMHO:
but it takes a little bit of study to get up to speed with it.
In my experience, it does a pretty good job. However, there is nothing stopping
you from creating a library of dark frames at different temperatures, and then
using the most appropriate one. IRIS or DeepSkyStacker can then scale the
library dark frame to more completely match the actual lightframe.
You can fid Duncan's website at: http://www.sfu.ca/~dmunro/
Written 27 Oct. 2007 Last Edited 29 Oct. 2007
© Andrew Kalinowski
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