Originally posted by ChrisPlatt When I started in photography the manual focus 35mm film SLR was most popular.
Back then the major camera/lens manufacturers kindly tried to standardize filter size.
Looking historically at it, it was normal to have a large stack of different filters back then. Polarizer, soft, star, orange, yellow, light blue, several ND and more. Today the need is much smaller, in my opinion a basic filter set consists of only two filters: a CPL and a ND4 or ND6 filter. Screwing and unscrewing filters are unnecessary cumbersome. Looking into the future, I wish those two filters gets integrated into the camera body. Both filters should be able to move in and out of the optical path and CPL should of course be turnable. Preferably by a wire system. This would save much cumbersomeness, eliminate the filter size problem, total cost and bag space. It can be hard to find space inside a DSLR, but mirrorless should have space enough.