Quote:
Originally Posted by Finnkare
Well, after thinking about this I have come into the conclusion that there's no problem with step up rings as long as the ring is wide enough. An how wide? In order to ensure that the filter does not cause more vingetting than at the starting point, the width of the step up ring has to be at least 2x the height of the threaded part of the ring + the original filter thread. My logic says that if you go n mm left and right horizontally, and then n mm up, the light beams can travel just as they did without any added height on the lens barrel.
|
After some more thinking, maybe I'm a bit wrong here anyway. Maybe the principle above is true with a lens with diagonal AOV of 90 degrees, a 21mm. With longer lenses one could use also smaller rings.
Maybe.
