"Rivergoat" wrote in message
...
I'm thinking I was right on the border of exceeding capabilities on a
recent high altitude shoot. Using a Nikon N90s with circular polarizer
and an 81B warming filter (sorry, I just can't afford a warming
polarizer just now), and the lens hood (on a 24-120 Nikon), some shots
seemed to exhibit a slight vignetting. I am assuming that's due to the
stacking? Is there a rule of thumb, should I be best off not using the
hood when I need to stack? All in all, though I still got some very
nice shots on the trip....

I believe Nikon lenses are designed such that they may take one filter
without vignetting. Longer lenses don't vignette as much, but my 28mm
always vignettes with two filters stacked.
-Kevin