Steve, Pentax screwmount lenses are so good--and so affordable--that I wouldn't consider third-party lenses except where there are conspicuous gaps: Fujica 400/4 and 600/5.6 in M42, for example, a fast multicoated 20 like the Carl Zeiss Jena 20/2.8, a fast portrait lens like the Carl Zeiss Jena 80/1.8, or a fast 200 like the Vivitar Series 1 200/3. All of these have an autodiaphragm switch that will work with your F. Most Series 1 lenses were not multicoated until the K-mount versions, but the Vivitar Series 1 28/1.9 screwmount is an especially nice lens that is multicoated and yields beautiful color and sharpness. How good is it? I kept my 28/1.9K and just sold my Pentax SMC 28/2K, the Pentax twin of the Zeiss Distagon.
Consider the Pentax SMC 105/2.8. You could look months finding one in K mount; it's yours for the taking at $125 or less in screwmount. Many believe that the Super Takumar 50/1.4 and SMC 50/1.4 set a benchmark for build quality and sharpness that has today's 50s still playing catch-up. Paul Franklin Stregevsky - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
