Data sheet: Asahi Super-Takumar 105 mm f/2.8

Pekka Buttler, 08/2026

Specifications

The table below summarises the lens’ key specifications (measurements are based on the pictured sample):

Brand:	Asahi Opt.Co. (Pentax)	Lens name	Super-Takumar 1:2.8/105
Focal length(s)1	105 mm	Angle-of-view2	16 °
Maximum Aperture	f/2.8	In Production	1966–1971 (this version) 1963–1971 (all versions)
Lens mounts	M42	Subfamily (if applicable)	––
Length3	63,7 mm	Diameter4	58,0 mm
Filter ring diameter	49 mm	Weight	280 grams
Lens element count	5	Lens group count	4
Aperture blades (S/R/C)5	6 S	Focus throw	285 °
Minimum focusing distance (measured)	118 cm	Maximum magnification (measured)	1:8,9
Has manual aperture ring	YES	Has Manual focus ring	YES
Aperture mechanism type	Auto/Manual	Aperture click stops 6	2.8-4•5.6•8•11•1622

Further notes:
• Pentax is one of the (many) manufacturers who used to (from 1958–1977) offer 100–105 mm portrait lenses. See ‘versions’ for a quick rundown of that genealogy.
• This is an auto aperture M42 lens (standard M42). Besides aperture and focus rings it offers a Manual/Auto switch to steer aperture functionality.
• The lens does not have an integrated hood. Asahi/Pentax used to offer a thread-mounted hood that could be used on the Super Takumar 105/2.8 and 100/4 lenses. Should you want, you can also use any 49 mm thread-mounted tele hood.

Versions

The table below summarises the major steps in the genealogy of Asahi/Pentax 105 mm f/2.8 lenses.

Years	Mount	Name / family	Mainline specifications	Optical design	Aperture mechanism type	product #	filter diameter	Notes
1958–61	M42	Takumar	105 mm f/2.8	4e/4g	preset	331, 44310	46 mm	2 silver rings, aperture ring at front.
1961–63	M42	Takumar	105 mm f/2.8	5e/4g	preset	349, 43490	49 mm	(all-black)
1959-63	M42	Auto-Takumar	105 mm f/2.8	4e/4g	semi-automatic aperture (automatic stop-down, manual opening)	340, 43400	49 mm	2 silver rings, aperture ring at back.
1963–64/66	M42	Super-Takumar	105 mm f/2.8	5e/4g	auto aperture	350, 43500	49 mm	all-black, ribbed aperture ring
1964/66–71	M42	Super-Takumar	105 mm f/2.8	5e/4g	auto aperture	43501	49 mm	all-black, ribbed aperture ring [this lens]
1971–75	M42	Super-Multi-Coated Takumar	105 mm f/2.8	5e/4g	auto aperture and open aperture metering on compatible cameras.	43502	49 mm
1975–77	Pentax K	SMC Pentax	105 mm f/2.8	5e/4g	automatic aperture	23240	52 mm	rubber focus rings.

History of Asahi / Pentax

The camera business today known Pentax was founded in 1919 as Asahi Kogaku Kogyo (Asahi Optical Company). Initially the company manufactured lenses for eyeglasses, later diversifying into projection lenses and even later into photographic lenses, supplying lenses for camera makers such as Konishiroku (Konica) and Molta (Minolta) and binoculars.

In 1952 – the year of the Helsinki olympiad – Asahi released the Asahiflex, the first Japanese 35 mm SLR. Together with its SLR cameras, Asahi introduced a line of lenses that carried the name ‘Takumar’, in honour of the founder’s brother.

In 1975 Asahi/Pentax introduced its own bayonet mount – The Pentax K mount – and phased out the production of m42 lenses and cameras. The name Takumar would remain on Pentax lenses until 1979 (and made some sporadic reappearances). The Pentax K mount is still a current mount, but it has several versions/generations. For details, see the JAPB article on the Pentax K mount.

Pentax was among the handful of Japanese camera manufacturers to keep up with the introduction of autofocus SLR cameras, and even survived the shift from film SLRs to digital SLRs (albeit somewhat struggling).

Adapting

If you want to natively mount this lens you need to find a functioning m42 mount film camera. Luckily that should be relatively easy as m42 bodies were produced in their millions and most of them lack features that are especially likely to have deteriorated to the point of making the entire camera inoperable.

Adapting this lens to a mirrorless, full-frame digital camera is a breeze thanks to the lens having full manual controls (aperture ring, focus ring). You simply need a dumb adapter from m42 to your mirrorless system (And set the lens in manual mode to be sure the aperture works as you intend).

Due to the medium flange focal distance used by the m42 mount (45,46 mm), whether you can adapt this lens to dSLR/SLR mounts depends on which dSLR mount: Canon EF, Four Thirds, Minolta/Sony A and Pentax K can mount m42 lenses using a simple adapter ring. Nikon F on the other hand is not as problem-free, and – to retain anything near infinity focus – the adapter will necessitate corrective optics. In all cases, your camera will work only in stop-down metering.

Footnotes

1. Focal length is (unless stated otherwise) given in absolute terms, and not in Full-frame equivalent. For an understanding of whether the lens is wide/tele, see ‘Angle-of-view’. ↩︎
2. Picture angle is given in degrees (based on manufacturers’ specs) and concerns the diagonal picture angle. Rule of thumb:
   > 90 ° ==> Ultra-wide-angle
   70–90 ° ==> Wide-angle
   50–70 ° ==> Moderate wide-angle
   40–50 ° ==> ‘Standard’ or ‘normal’ lens
   20–40 ° ==> Short tele lens
   10-20 ° ==> Tele lens
   5-10 ° ==> Long tele lens
   < 5 ° ==> Ultra-tele lens ↩︎
3. Length is given from the mount flange to the front of lens at infinity. ↩︎
4. Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
5. S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎
6. Numbers equal aperture values on aperture ring; • intermediate click; – no intermediate click. ↩︎