----- Original Message ----- From: <[EMAIL PROTECTED]> Subject: Re: Sigma 600mm f/8.0 Mirror Lens Sample Photos and Specifications
> Is there an optical reason why a mirror lens can't achieve high > resolution? I wouldn't think so. As Bill said, the only real drawback is > the bokeh. And with digital photography that can sometimes be repaired. They are finicky to make. It's more difficult to align mirror lenses than refractors, from what I've been led to understand, and, of course, a front silvered mirror can be all over the place for quality, and I suppose might be prone to oxidizing of the silvered surface. Having said that, there is a lot of very high end telescopes out there (Hubble?) that are essentially just great big mirror lenses, so the quality is there, as long as the manufacturer cares to put the effort into it. There are a lot of cheap reflector lenses out there, and, like all cheap lenses, optical quality is probably going to be compromised somewhat. The Tamron 500/8 was not a cheap lens, although it certainly wasn't in the price league of the 600/5.6. I'll dig it out and play with it a bit over the next day or so and post something from it. Probably not high art, but I'll try for something more interesting than a brick wall. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
