What, if any, would be the problems in using a 77 - 72 step down ring to mount a polariser filter? Would it depend on the lens?
But if you're using a crop body, it may not make any difference as only the centre of the lens is used.
I think you'll find that all the lens is used but only the centre of the resultant image is used.
Bob
I think you'll find that all the lens is used but only the centre of the resultant image is used.
Bob
Which way are you stepping down?
1. 77mm filter down to a lens with 72mm thread
2. 72mm filter up to a lens with 77mm thread
If 1 you shouldn't see any issues
If 2 you may see some vignetting
Steve