Way back in 1986 I purchased a Tamron SP500 f8 Mirror (Telephoto) lens from a camera shop in London, it was second hand and cost around £150 back then.
The lens is reviewed very well here : Photozone review
I came across this lens again while sorting out some equipment last week and could not resist taking some images with it, so I put it onto my Sigma x3 camera and took a walk with both through some local fields.
I am not going to reviews the lens as such here as this is done so well in the above review, what I would say however is that this is a manual focus lens that is able and very capable of producing some very detailed and delicate images.
I really enjoyed using it again, if you are looking for a lens that is quick to use then this lens is not for you. If you take your time while creating your images however then this lens offers some very different and interesting results. I very much liked the shallow depth of field, there is something about the design in a mirror lens that produces a very find focus area in the image results.
I also felt that the combination of this lens alongside the sigma x3 sensor, produced some of the closest results to using film that I have noticed while using a digital camera.
The lens is very sharp, it produces wonderful colour and contrast, focuses down to 1.7 meters from the nearest subject and has a very shallow depth of field through out its focus range. Photographers spend a lifetime looking for lenses that have these features along with very distinctive results, if you can give this lens the time to learn how best to use it, I feel you will love it !
These lenses are often for sale on Ebay, if you want to purchases one and try one out !