I don’t have a lot of use for an 800mm lens. But, now and again, it’s a useful tool to have when shooting wildlife, especially from long distances. It’s a catadioptric lens, meaning it’s a mirror lens. It’s an unusual piece in that the glass is one solid part. It was unusual and expensive when it was made, so not very many were sold. It’s also a decent piece of glass and can get the job done.
On my crop-sensor Nikon D300, it’s the equivalent of a 1,200mm lens. That’s a lot of reach. I have a Nikon 1.4x extender that I can use (and lose a stop), but there’s not much out there that needs to be shot that can’t be reached with an 1,800mm lens.
I made some minor adjustments to the image, mostly exposure and contrast, and added a bit of sharpening as a final step. Enjoy.