Well, that mirror lens isn’t too bad. I just have to be careful how to use it so as to avoid the circles and to get good shots. Here is a shot of a Mourning Dove in my neighbor’s back yard. Best guess, based on the distance scale on the lens, this guy was about 150 – 200 ft. away! Still he’s rendered pretty sharply.
I just might get used to this lens! I bought it on eBay about 3 weeks ago but haven’t used it too much. It’s not exactly an everyday lens unless you are photographing wildlife. It’s still not up to the quality of the $8,000 Nikkor 5oomm f/4, but then I only paid $400 for it!