I'm gonna reply, but not about astrophotography. I have two mirror lenses, both 500mm f8: Lentar and Spiratone. the Spiratone is much smaller than the Lentar.
I shoot the Lentar a lot. It is not a good lens, particularly with regard to contrast. But it _is_ a 500 and it was cheap. I've found that boinking up contrast and saturation in Photoshop makes a surprising difference with the Lentar. If it only didn't give those weird out of focus highlights, I'd now be in love with it. But it's probably going to be my only "really long lens" for a long time to come. The Spiratone I've rarely shot, mostly because it is a true f8, and is about a stop slower than the Lentar, which has a bigger front element and less DOF than the Spiraton. The Lentar also has a nice tripod mount. -Lon Doug Franklin wrote: > > Howdy, Peter, > > On Tue, 10 Dec 2002 04:20:10 EST, [EMAIL PROTECTED] wrote: > > > I would say generally that mirrors are never quite going to perform like > > regular lenses, however if you can provide a stable platform that will help > > considerably. > > You know, I've seen this opinion expressed many times. It's a very > common opinion within photographic circles. I've even fallen under its > spell, though I have no experience with "mirror" lenses. > > But in astronomy, even at the low end of the price and capability > spectrum, folks seem to prefer "mirror" telescopes. Is there some sort > of paradox here, or does it all have to do with the prohibitive expense > of a refractive telescope/lens with 6" or larger elements? > > TTYL, DougF KG4LMZ
