lens?

[Christi V]

what is a mirror lens and what do they mean by T mount....??

[Saralonde]

This might explain a mirror lens better than I could.

[Aegea]

And to answer the second part of the question, T-mount is an interchangeable mount system that uses inexpensive brand-specific adapters. So if you have a T-mount lens, you can buy an adapter for Canon, for Nikon, for Pentax, etc., etc. The drawback is there is no electrical or mechanical connection or linkage, so no autofocus, automatic aperture control, etc. Of course, mirror lenses don't any of that anyway (except, IIRC Minolta did produce an autofocus mirror lens at one time).

[OsmosisStudios]

Nikon made an AF one too. It was a while ago, and terrible.

[kuvahmagh]

Of the major manufacturers, currently only Sony (formerly Minolta) offers a 500 mm catadioptric lens for their Alpha range of cameras. The Sony lens has the distinction of being the only reflex lens manufactured by a major brand to feature auto-focus (aside from the identical Minolta-manufactured lens that preceded Sony's production).

From the Wikipedia article on Mirror Lenses: Catadioptric system - Wikipedia, the free encyclopedia

[spazoid1965]

Originally Posted by Aegea

And to answer the second part of the question, T-mount is an interchangeable mount system that uses inexpensive brand-specific adapters. So if you have a T-mount lens, you can buy an adapter for Canon, for Nikon, for Pentax, etc., etc. The drawback is there is no electrical or mechanical connection or linkage, so no autofocus, automatic aperture control, etc. Of course, mirror lenses don't any of that anyway (except, IIRC Minolta did produce an autofocus mirror lens at one time).

Great desciption. But to add a little. The T-mount itself is a 42mm thread to which these adapters screw onto. The adapters mount onto your camera. Then the lens will screw into the adapter.

While the Mirror lenses will have a lower quality than a true lens of the same lenth. There are some advantages of mirror lenses. They are lighter, smaller, and a whole lot cheaper. If your trying to sell your photos don't waste time with a mirror lens. If you have the "Joy of Photography" mindset. Then go ahead and get one. It's the cheapest way to get out to that focal lenth.