Conventional Telephoto vs. Mirror lens

[pittmancw]

I am thinking about buying a manual focus, 500mm prime lens with a 2x converter for my old Pentax K1000.

Anybody out there have any solid opinion on which is better, a regular telephoto or a mirror lens? Also, any recommendations on make/model would be mucho appreciado!

[another view]

The big problem that a lot of people have with mirror lenses is that they make donut-shaped highlights in the out-of-focus areas. Every once in a while you'll see the effect, maybe sunlight glaring off a lake or something. It's almost a special effect like a fisheye lens - it can be kind of interesting once in a while but definately not something you want every day. In low contrast situations this probably isn't too much of a problem though.

Mirror lenses are also fixed aperture lenses, usually f8 which doesn't give you much depth of field. This makes the donut-shaped highlight syndrome all that much more of an issue!

There are some fairly inexpensive 500mm primes that you might look at - I used to have a Sigma 500mm f7.2 which wasn't too bad. On ebay, you might find one for around $3-$400 but I'm not sure if they made them in a "K" mount.

[Outdoorsman]

but I'm not sure if they made them in a "K" mount.

They make adapters. I used to have one for my K1000 (God rest its soul) that made old Vivitar screw-mount lenses work for the Pentax mount (since I was shooting both systems then). I also had to get an adapter for a 500mm telephoto (piece of CRAP!) to fit the Pentax. The lady at the shop called it a "t-mount" and the box it came it called it a "t-mount" but what difference does it make as long as it works? Pittmancw: are you gonna buy one of those el cheapo $150 500mm lens/2X teleconverter kits? If so, DON'T!!! I did, and it was a waste of money. It's a real turd of a lens and you'd be better off with the mirror lens. Get a better telephoto or suffer with the constant-aperture mirror lens. But Don't Buy The Junk Lens!

[mikishots]

Stick with the telephoto lens (glass) if at all possible. The specular highlights are the least of your worries - it's the crappy contrast that will get you every time. You'd be hard pressed to find a mirror lens with good contrast. It's like shooting through a diffuser all the time.