I'm just making a semi-educated guess, but I think you're speaking of the Takumar, and it has come in both M-42 screw mount and K-mount bayonet? That's all I can think of. If so, their performance whould be essentially identical to each other, as most bayonet SMCs are 'merely' M-42s with bayonet mounts. So I'm given to understand...
Frankie Lee wrote: > > There are two versions of SMCT 135/2.5. Do they have the same optical performance? >Thanks. I have no info on serial numbers, and don't know where to get any! :^( However, as a single point of reference, I have a 135mm, f/2.5 SMC Takumar, M-42 mount, s/n 4,961,35x, the "x" being the obfuscating numeric character... ;^) keith whaley
