[victorio]

I own a pentax mz-5o camera, I now need to know if I can fix a pentax 80-200mm auto focus zoom lens baynet ,is this compatible with my camera..

[gp1806]

Quick answer YES. It should work fine if the lens is working properly.

[RKKS08]

I own a pentax mz-5o camera, I now need to know if I can fix a pentax 80-200mm auto focus zoom lens baynet ,is this compatible with my camera..

If the lens has an aperture ring (where you can set the aperture manually), with a MZ-50 the exposure will only be correct if the aperture is set either to "A" position or to the smallest value ( = fully open aperture). This is because the 2-digit MZ cameras like MZ-10, MZ-30, MZ-50 only allow for somehow reduced communication between body and lens.
I think all Pentax AF zooms 80-200 do have an aperture ring, but I am not sure.

[GerryL]

Welcome to the forums Victorio!
Any Pentax lens even to the screw mount ones (with M42 adapter), you will be able to use on your Pentax MZ-50..even if you move to digital later on.
So whether it be a manual focus lens or an AF lens, it would be compatible. You only have to read the manual on how to deal with the manual focus lenses for proper exposure.
The only lenses that are not recommended on the film SLRs are the DA versions or for digital or DSLR's since if the lens usually causes vignetting on the wide end.
Rule of thumb: You can use any Pentax lens ever made for SLR's on the Pentax DSLR's but you can't do it vice versa with the reason stated previously because of the APS-C sized sensor and crop factor.
Check out the lens review section of the forums too:
Pentax Reviews - Pentax Lens Reviews & Pentax Lens Database
Third-Party Lenses for Pentax - Pentax Third-Party Lens Review Database
..and the Pentax camera reviews:
All Pentax Cameras - Pentax Camera Reviews - DSLR and Film SLR Database