Anyone seen/experienced a Vivitar 800mm f/8 Mirror Lenses?

I just went through dozens of retail sites and a bunch of search pages and no one seems to have any type of review or comment about this thing.

Has anyone here had an experience with one?

I know the Pros/Cons about mirror lenses. But it is so ridiculously cheap, it certainly wouldn't hurt to try one on good sunny days. :)

I had a 650mm f/8 (I forget the brand) back in the late 80's. Never used it more than a handful number of times. Light and compact obviously, but image quality left a lot to be desired.

Would be great as a spotting scope.

There are some mirror lenses that are actually pretty good from what I have read. Even Zeiss mirror lenses exist, although that is beyond my price range at this time. I've read some Ohhs and Blaas about Vivitar which is why I was wondering.

I finally found someone with test shots of it. Sure, it looks a tad on the soft side, but some of these look pretty good IMHO! What do you guys think?

http://www.clubsnap.com/forums/showthread.php?t=625274

A little soft, but not as bad as I was expecting. I think the way he has the backgrounds so dark is a good use for a lens like that. The bokeh from mirror lenses is usually not good. His dark backgrounds took that aspect out of play nicely. Some of the photos that are linked to in that post give some good examples of the donut bokeh.

Yeah, I saw those donuts. Pretty funny. I guess the trick is to make sure you are not getting any light reflections into the camera.

Those examples are under pretty controlled conditions and not typical of what you'd get in the field.

Imagine using them on dew covered mornings or with a lake in the background or with back-lit leaves surrounding a bird. Those donuts merge into a horrible pattern.

But can't beat the price for the focal length. Better to buy binoculars and use stalking techniques to get closer with shorter lenses :)