Tamron SP 500 mm f/ 8 Adaptall-2 model 55BB Lens

Cheap manual 500mm. All metal lens. Good focus throw. Easy to adapt to almost any DSLR (Canon, Nikon, Pentax).

It's fun to use.

Weaknesses:

Difficult to use handheld, difficult to nail focus, too dark (it's a f/8). Lack of sharpness (pictures needs to be edited).

Comments:

Don't be fooled by this old vintage 500mm f/8 cataddrioptic lens. If the lenses are clean with no haze nor separation, then you will be able to take nice shots with patience and perseverance.

Pictures from this lens will always lack of contrast, so you need to edit all shots or use a camera specific tuned profile if you shoot in JPEG.

This lens is best suited for stationary objects like architecture details or flora. For wildlife it is a true hit in the ass but fun too, when you get it right you will be happy for the rest for the day.

With non stabilized bodies you will need to use exposures values starting at 1/1000s, that means that yout ISO setting will also increase a lot ins come light situations.

So keep calm and enjoy.