Came across this on a site which has banned me ....
"I came across an old zoom lens I used to use. It’s a “sun” brand, and fits a pentax (thread-mount) camera, and is 85—210 size. Do you know if there is any use for something like this now?"
It could be rubbish and only useful as a paper-weight as one snooty person suggested ... on the other hand if it is a 'Thread Pentax' that means to me that it has a'M42' thread and adaptors to EOS an MFT are available ... I have both and my legacy lens are all M42 Pentax.
I do not know the 'sun' brand an it ould be AOK maybe not but if cheap enough worth a try.
Sun lenses ....http://allphotolenses.com/lenses/brands/c_101.html
The reviewer suggests it is a good quality lens
It appears to be a constant f/4 like my Tokina.
A couple of shots when I got my APS-C and fittied the lens to it. Shot in A mode the camera picks the shutter speed but I had to focus.
Trolley Derby shooyting from side of road ...