Using Image Calibration Techniques to Reduce Noise in Digital Images: http://www.photo.net/learn/dark_noise/
What an interesting idea – guess what I’ll be trying out tonight !
(Lee asked if this was setting the ‘Black Balance’ of an image – not a phrase I’d heard before, but I like it a lot !)
Dave
I heard about this technique *yonks* ago, but had forgotten all about it, due to not having a decent image manipulation program, so thanks for reminding me. I gave it a shot last night, except that when I took the “covered” shot, I was trying to hold it still to avoid camera shake on a 0.25S shot. Doh 😳
However, the results were worth it; a grainy ISO1600 shot came out rather better after use of the image subtraction. Thoroughly recommended 🙂