|
I have seen other people say the histogram should be in the 33 % to 50 % region and that is what I have been trying to get. I do have to move the black point a lot in PS, but some of it may be due to the final steps in processing in IRIS.
A consideration with choice of ISO is the dynamic range..apparently this is inversely related to the ISO.
My practical experience has been that a single ISO 1600 shot of say 8 -10 minutes -even with the filter- from a light polluted location -is so noisy as to be unusable.
Somewhere between ISO 200 and 800 and maybe it is dependent on ambient conditions...ISO 800 if you have a really dark site?
On Terry Lovejoy's site someone has done an analysis of the relative merits of varying exposures and ISO settings.
Have to go now but will try to find and post it here
Thanks for the nice comments anyway.
|