Thanks, John. It all helps. Now I'm faced with selling a couple of my stop-down aperture lenses and replacing with full-aperture metering lenses. I bought a couple when I was 'unaware.' <g> I really hate getting rid of my Super Takumar 135mm f/3.5 M-42 mount. It's so smooth and small, and almost brand new! If there's an SMC Takumar version of the same lens, that has the aperture lever, either M-42 or K-mount I'll buy it!
I have both a Pentax MG and a Spotty F, so I can use either lens. I suppose I should shoot for an M-42 version, because I can put a bayonet adapter on the M-42, but not vise-versa! I do have another 135, an f/2.5 version, but it's so much bigger and heavier than the littler f/3.5 version... All of your info helps a lot in increasing my understanding of the various Pentax lenses. One question left...there's a _tiny_ spring loaded pin on the rear _mounting_ face of my M-42 lenses. It's located about 1/4" CCW from the solid machined stop on the aperture ring on the rear, but the pin itself is on the mounting face. What is it? Keith Whaley John Coyle wrote: > > Hi Keith: > Here's my understanding of the various combinations of Takumar, SMC > etc: > Takumar was the original name for the non-auto diaphragm lenses of the > 1950's - 60's. Some of these were pre-set diaphragm lenses, with an > additional control ring. You focussed these at full aperture, then > stopped them down for exposure (and for metering with the Spotmatic and > later). > Auto-Takumars were introduced with semi-automatic diaphragms, where you > opened up the aperture for focussing, and the camera closed it on > pressing the shutter release > Super-Takumars were introduced with the fully auto-diaphragm mechanism > when the Spotmatics, SV's and S1a's were produced, beginning about > 1963-4. Lenses of 200mm and over continued to be produced with no > automatic diaphragm, and remained designated as Takumar or > Tele-Takumar, whether pre-set or manual diaphragm. > (Source: 'Asahi Pentax Guide', Focal Press, tenth edition, August > 1967) > > Super-Takumar, then, does not necessarily refer to the coating used. > > Super-Multi-Coated coatings were introduced in 1971, and the lenses > were Bagdad "Super-Multi-Coated" in full. Pentax lenses were coated > prior to this, but part of the marketing of the SMC was that it was > more efficient for less thickness of coating - test reports at the time > said it blew away competitive coatings, and IIRC, had been either > jointly developed with, or licensed to, Carl Zeiss, who designated it > as T* coatings, or something similar. These seven-layer coatings, > according to the LX brochure, reduced the loss of transmitted light to > 0.2%, compared with 1-2% for conventional coatings. > > It was with the change of mount to the bayonet that Pentax lens were > designated "Pentax" rather than "Takumar", and the SMC abbreviation > replaced the full text. I have a brochure for the original "K" series > release in which all of the new lenses are named "SMC Pentax" with the > suffix "Shift", "Macro", etc., where appropriate. > > The generally physically smaller lens range introduced for the M series > was designated "SMC Pentax-M". > > The LX brochure lists both SMC Pentax-M and SMC Pentax lenses, and I am > not sure whether the non-M ones are new introductions or a continuation > of the K series: for example the SMC Pentax 15/3.5 appears in both > brochures, but the SMC Pentax 30/2.8 only appears in the LX list > > The "Takumar Bayonet" range, introduced as a budget range in the later > '80's, did not carry the "SMC" tag at all, and, while my example of the > 28/2.8 is optically good, it undoubtedly would be prone to more flare > than the M-series, which looks like a totally different design. > > HTH > > John Coyle > Nicholas John Consultants > Brisbane, Australia
