Mirror Lens?

BAmereihn · May 23, 2010

What is it, what is it for, and what if any is the benefit over a regular lens?

TiCoyote · May 23, 2010

People ask this fairly often. If you're talking about those $100 500mm fixed aperture lenses, stay away. They are cheap, and so are the results. It's just a cheap and lightweight way to build a long zoom, but the technology doesn't really support the application.

BAmereihn · May 23, 2010

i don't have any interest in buying one, most are made by no name companies so they cant be good

Derrel · May 23, 2010

If you would like to hear the positive side of mirror lenses, and a little bit of background on them,how to use them, and so on, do a Google search for the terms mirror lens + Herb Keppler. Herb Keppler wrote a few articles for Modern Photography magazine, on the subject of mirror lenses. Mirror lenses are actually pretty easy to stabilize and shoot hand-held or braced on window mounts, railings, beanbags,monopods, etc.

The low contrast images out of most mirror lenses used to be a really big problem when we shot color slide or negative film, but now that images are digitally captured, it's quite easy to boost contrast very easily in post, to almost any degree desired, so that eliminates one of the biggest weaknesses of most mirror lenses--low image contrast. The doughnut highlights make some scenes look odd, or horrible, depending. There HAVE been some good mirror lenses made over the years--the designs are out there, but the $109 models are not of the highest quality.

Since mirror lenses are manual focus only, with the exception of the truly NEW Sony 500mm autofocus lens, and ,mirror lenses have no diaphragm, it is very possible to build mirror lenses with interchageable T-mounts, which allows the lens to be adapted to different mount systems. Also, it's very easy to adapt NIkon F mount and M42 thread mount mirror lenses to Canon EF-mount cameras with a very simple adapter. Mirror lenses often show up in used departments, due to a lot of factors.