Originally posted by RTogog Hi,
I finale found my late father old Pentax lenses which is also my favorite’s lenses .All are prime lenses.Those are Pentax SMC-M 28 f2.8, 35 f 3.5, 50 f1.4 and 200 f4. In film era this focal length was my favorites to go along when in hiking, small, light & compact on my backpack.
These time new versions are still can be found (FA) or undergo w Pentax new lens roadmap (DA). I only occasionally took pictures w film, but most the time use digital now.
Nice find, very compact and good quality.
Originally posted by RTogog I would like to know is there slightly differences between the old generation of lenses with later version (FA, DA) ,if this old lenses to be used on DSLR body, in term of sharpness, colour rendition, CA, flare resistance & the quality of bokeh. With my intended use of these lens, an auto focus is actually not so important.
These are all great questions. First of all, the M series was not generally considered the best by Pentax. That opinion differs from lens to lens, though.
I'm a big user of old glass (yes on my digital SLRs) and find that the digital coatings are not as useful to me. The SMC coatings starting with the screw mount SMC Takumars are very good and very close to the superb coatings we see today. One big benefit to the 'digital' coatings is the reduction in flare from the reflection off the sensor - but compared to (for example) similar Minolta film lenses, the old Pentax coatings do *much* better in this regard. It will probably only ever be noticeable with macro lenses - at least that is the only place I've ever seen it become a problem.
In terms of sharpness, color rendition, and flare resistance (except for the note above) they will compare closely to their modern equivalents. I did a vertical test of 50/1.4 lenses (sorry, not the M version) and I found that from the oldest Takumars to today's FA50, the overall image quality has gotten better, but it is *really* slight and not noticeable in 'real world' shooting IMO. So I'd give them an equal grade in this regard.
As far as bokeh, I personally own the M28/2.8 and it is OK, not great. The M35/3.5 I'm sure is pretty close to the Takumar 35/3.5 which has a neutral bokeh IMO. Of course it is at f/3.5 wide open, but you're not really shooting these lenses for the wide aperture bokeh anyway.
The M50/1.4 is going to be wonderful. The M200/4, which I owned for a short bit, is very good too.
For CA - the M28/2.8 has low CA compared to my other lenses. (I don't have a modern 28mm.) I'm sure the M50/1.4 and M200/4 are in the low-to-middle range as far as CA and purple fringing, but to be honest the modern Pentax equivalents are probably just as bad. My FA50/1.4 is every bit as bad as my (ca. 1971) Super-Multi-Coated Takumar 50/1.4. There isn't really a modern equivalent to the 200, and I can't comment on the 35.
In short, they are decent lenses. It would take a good bit of $$$ to buy them all on eBay, and I would be happy using them. I don't think you'll be disappointed at all.