The Tamron Adaptall SP 500mm f8 is a compact telephoto mirror lens that packs a fair bit of magnification into a package less than 10cm long. To be fair, it's also about 9cm wide, but that's still pretty packable for a 500mm lens. Downsides to this type of lens is that it's manual focus only, somewhat dim at f8, you can't change the aperture at all, and out of focus highlights look like little donuts. But if you need a lot of magnification every once in a while, you can't beat the convenience. In excellent condition, with clean glass and minor wear. Includes case, hood, plus yellow, orange, and UV filters; an ND filter is not included here. This lens is provided with a Pentax K mount, but its Adaptall interchangeable mount system means that it can be used on nearly any camera with an appropriate adapter (additional adapters not included.)