Pentax (Takumar) Pentax-M Heritage

Overview

The reviews provided concern the Takumar family of lenses made by the Asahi Optical Co., Ltd., the Japanese company founded by Kumao Kajiwara (who named the lenses after his painter brother, Takuma Kajiwara) that eventually became Pentax and is now a subsidiary of Ricoh. Asahi Optical produced the famous Spotmatic camera (introduced 1964, an early through-the-lens metering SLR) and a wide range of M42 screw-mount Takumar lenses. The most celebrated of the family is the Super-Takumar 55mm f1.8, described in the reviews as 'an all-time classic and one of the best vintage lenses commonly available today' — inexpensive, solidly built, and delivering good image quality with plenty of character. The 55mm f1.8 line evolved through several named tiers: Takumar (1958), Auto-Takumar, Super-Takumar, Super-Multi-Coated Takumar, and finally SMC Takumar (through the mid-1970s). Note that the reviews describe M42 screw-mount Takumar lenses, whereas the lens named here is a 'Pentax K' mount Pentax-M — the K-mount successor line — for which the supplied reviews offer no direct evidence. One established piece of jargon that the reviews DO support is 'radioactive': certain Takumars use thoriated glass and exhibit slight radioactivity (and associated yellowing). People love these lenses for their affordable price, solid all-metal build, and rendering character. Company renaming to Pentax Corporation occurred as late as 2002.

Verdict: The supplied reviews document the M42 Super-Takumar 55mm f1.8 and SMC Takumar 105mm f2.8 rather than this specific Pentax-M K-mount lens, so a definitive rendering verdict cannot be grounded in the evidence. What the reviews do establish is that Asahi's Takumar/Pentax primes are prized for affordable, solidly built, all-metal bodies with superb focus feel and pleasing character — making them excellent, characterful choices for enthusiasts adapting vintage glass. Specific traits of this Pentax-M lens are unknown from the provided sources.

Community Insights

What people love

Affordable pricing and wide availability on the used market (as noted for the Super-Takumar 55mm f1.8)
Solid, fully metal old-school build quality
Exceptionally smooth focus ring — described in reviews as operating 'as smooth as silk,' among the best mechanical focus feedback tested
Good image quality with plenty of 'character' at a low price point

What people dislike

Slight radioactivity from thoriated glass in some Takumar variants (can cause yellowing)
No weather sealing on vintage examples
Requires an adapter to use on modern digital cameras (noted for M42 examples; the K-mount version mounts natively on Pentax bodies)

Pro Tips

Appreciate and exploit the smooth manual focus ring for deliberate, precise focusing
If you own a radioactive thoriated-glass variant, note that UV exposure can reduce yellowing over time (general knowledge; specific behavior for this lens is unknown)
On a modern camera, confirm the correct mount interface — K-mount Pentax-M mounts natively on Pentax DSLRs while M42 Takumars need an adapter

Sources (1)

Web-grounded synthesissecondary

The reviews provided concern the Takumar family of lenses made by the Asahi Optical Co., Ltd., the Japanese company founded by Kumao Kajiwara (who named the lenses after his painter brother, Takuma Kajiwara) that eventually became Pentax and is now a subsidiary of Ricoh. Asahi Optical produced the famous Spotmatic camera (introduced 1964, an early through-the-lens metering SLR) and a wide range of M42 screw-mount Takumar lenses. The most celebrated of the family is the Super-Takumar 55mm f1.8, described in the reviews as 'an all-time classic and one of the best vintage lenses commonly available today' — inexpensive, solidly built, and delivering good image quality with plenty of character. The 55mm f1.8 line evolved through several named tiers: Takumar (1958), Auto-Takumar, Super-Takumar, Super-Multi-Coated Takumar, and finally SMC Takumar (through the mid-1970s). Note that the reviews describe M42 screw-mount Takumar lenses, whereas the lens named here is a 'Pentax K' mount Pentax-M — the K-mount successor line — for which the supplied reviews offer no direct evidence. One established piece of jargon that the reviews DO support is 'radioactive': certain Takumars use thoriated glass and exhibit slight radioactivity (and associated yellowing). People love these lenses for their affordable price, solid all-metal build, and rendering character. Company renaming to Pentax Corporation occurred as late as 2002.

https://www.pentaxforums.com/lensreviews/https://www.myfavouritelens.com/super-takumar-55mm-f1-8/https://opticallimits.com/vintage/vintage-lens-test-asahi-pentax-smc-takumar-105mm-f-2-8/