Comments about Pro Optic Pro-Optic 500 f/6.3 Mirror Lens for Pentax K SLR Cameras:

While I would buy this lens again, it is manual focus and is very hard to get the focus correct. I'm in the habit of taking multiple shots while playing with the focus, so I don't miss a picture. That being said 500MM at this price, WOW. I call this lens a poor man's 500MM.

Comments about Pro Optic Pro-Optic 500 f/6.3 Mirror Lens for Pentax K SLR Cameras:

I did not have high expectations for this inexpensive mirror lens. That is a good thing because it has fairly mediocre performance. It is light and compact compared to a conventional lens, but you will still want to use a tripod or monopod for added stability. For [*] around parks or the beach, this can be a fun lens. The image quality will not get you into National Geographic, however. A bit stiff focusing, and the T-mount has a little rotational slop to it that does not affect operation. This is a completely manual-operation lens. No lens hood. The lens is half the price of any of my other lenses, so I was willing to take the risk, and I'm keeping it.