HAHA so Some of you may laugh but I invented something that would save me thousands! I have Zeiss CP.2's and Canon lenses. Shooting wildlife on primes is kind of a dumb idea so I usually tend to use my CP's as studio or organized shoot lenses. I need ND's on my CP's but the stupid lenses don't have threads and each ND 4x5 square filter will cost from 400-almost 1k which is stupid compared to the Tiffen Variable ND which is $150. I already own the Tiffen so I took the right measurements on a piece of thicker cardboard and now I have this. I'll admit, it does look like a piece of SH..I.T but it works beautifully. It didn't cost anything besides a step up ring. the filter is perfectly intact and with no fear of it popping out. What do you think?