Originally posted by Mike Cash My guess, without actually bothering to visit a photo supply site to check, is that it allows you to save money when buying filters. Larger filters often cost more than smaller filters, especially when you get to such extreme sizes as 86mm or 95mm. It may also be that it is easier to find more variety of filters in 86mm than in 95mm.
It is possible that the step-down ring may cause some vignetting at the wider end of the zoom range, but you would need to test it to be sure. You can do that without actually using a filter. Just mount the ring and do some test shots.
Mike, thanks, will do. But it does make sense. Will do a few test etc.
regards
Arrie