I've had a little bug to try an extreme focal length lens. Like 800mm plus. I can't rationalize this desire, so I won't try. I've toyed with the idea of an older FD 800mm L lens, but can't justify spending >$1k for it. Same goes for a high end spotting scope (although I do like occasionally using my cheapo scope). There are cheap long lenses out there, but with the PL100-400 I can get better results just cropping. So, an option that I have semi-seriously been thinking about is picking up a Russian MTO-1000A or MTO-11CA (1100mm and 1000mm respectively). I don't think that the resolution would hold up to a 16-20Mp m4/3s sensor on it's own, but paired with a focal reducer, it...might...just...work. My hangup is that it would be a few hundred bucks to get the lens and focal reducer, for what might be a failed experiment. I was wondering if anyone had experience with either of these lenses, and if they're any good. I suspect that the money would be better spent on a quality telephoto (or literally anything else), but there's still a little part of me that thinks this could be a good idea. Thoughts?