Yes, the aperture control on a 50mm 3.5 Elmar is "fiddly", but its placement also means you are never going to use a filter. I know many people do not use any kind of protective filters on their lenses, and many photographers think you should not use protective filters because of impacts on image quality. But there are lots of Leitz LTM lenses with scratched front elements that make me want filter use as an option, not just for creativity, but also for protecting the investment. I use a Summitar and an LTM Nikon 50mm 2, btw.