Data sheet: Minolta MC Rokkor-PF 50mm f/1.7

Pekka Buttler, 01/2023

Specifications

The table below summarizes the lens’ key specifications (Measurements based on pictured sample):

Brand:	Minolta	Lens name	MC Rokkor-PF 50mm 1:1.7
Focal length(s) 1	50 mm	Angle-of-view 2	46,8 °
Maximum Aperture	f/1.7	In Production	1973–1977
Lens mounts	Minolta SR	Subfamily (if applicable)	MC (X)
Length 3	40,9 mm	Diameter 4	64,6 mm
Filter ring diameter	55 mm	Weight	232 grams
Lens element count	6	Lens group count	5
Aperture blades (S/R/C) 5	6 S	Focus throw	175 °
Minimum focusing distance	50 cms	Maximum magnification	1:7,9
Has manual aperture ring	YES	Has Manual focus ring	YES
Aperture mechanism type	Automatic	Aperture click stops 6	1.7-2.8•4•5.6•8•11•16

Further notes:
• From the introduction if the Minolta SR system until 1973, Minolta’s choice focal length for standard lenses was 55–58 mm – 58 for the fast fifty (f/1.4) and superfast fifty (f/1.2) and 55 for the nifty fifty (f/1.7–f/2).
• Also, Minolta would typically at the same time offer both a faster nifty fifty (typically f/1.7–f/1.8) and a slower nifty fifty (f/1.9–f/2)
• Starting in 1973, Minolta converted all its standard lenses to a 50 mm focal length, and cemented the maximum apertures of these in a four-tier structure that stayed unchanged throughout the remaining life of the SR system: f/1.2 – f/1.4 – f/1.7 – f/2.
• Up until 1977 (and the launch of the MD versions) Minolta lens names typically were followed by two letters: One signifying the number of lens groups, and the second signifying the number of elements. See Minolta elements and groups coding (click for details).
• This lens comes from the first generation of Minolta 50 mm (faster) nifty fifties.
• This lens was offered as a kit lens for many mid-level Minolta cameras in the mid 70s.
• The original Minolta 55 mm thread lens hood might be hard to come by, but most 55 mm thread standard lens hoods should work.

Versions

The table below shows the genealogy of all Minolta f/1.7–1.8 standard lenses:

Name (on lens)	Variant & Generation	years	focal length	max. aperture	min. aperture	elements	groups	filter thread	weight
AUTO ROKKOR-PF	AR I	1958-1962	55	f/1.8	f/22	6	5	55	260
AUTO ROKKOR-PF	AR II	1962-1965	55	f/1.8	f/16	6	5	55	275
AUTO ROKKOR-PF	AR C	1965-1966	55	f/1.8	f/16	6	5	52	210
AUTO ROKKOR-PF	AR C *	1965–1966	55	f/1.8	f/16	6	5	52	210
MC ROKKOR-PF	MC I	1966-1970	55	f/1.7	f/16	6	5	52	225
MC ROKKOR-PF	MC I *	1967-1970	55	f/1.7	f/16	6	5	52	230
MC ROKKOR-PF	MC II	1970-1973	55	f/1.7	f/16	6	5	52	230
MC ROKKOR-PF	MC II *	1970-1973	55	f/1.7	f/16	6	5	52	235
MC ROKKOR(-X)-PF	MC X	1973-1977	50	f/1.7	f/16	6	5	55	240
MD ROKKOR(-X)	MD I	1977-1978	50	f/1.7	f/16	6	5	55	195
MD ROKKOR(-X)	MD II	1978-1979	50	f/1.7	f/16	6	5	55	195
MD ROKKOR(-X)	MD II	1979-1981	50	f/1.7	f/16	6	5	49	160
MD	MD III	1981–≈1995	50	f/1.7	f/22	6	5	49	165

Adapting

This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need a Minolta SR (SR/MC/MD/X-600) film camera. Luckily these are quite easy to find. To use the lens’ full designed capabilities, a Minolta MD-compatible body (any Minolta SR body launched after 1977) is most recommended..

Thanks to being a fully manual lens (manual aperture, manual focus), the lens can be adapted to all mirrorless cameras using a suitable adapter. Moreover, a simple ‘dumb adapter’ will do the job perfectly. Thanks to the popularity of the Minolta SR mount, the availability of adapters to all mirrorless mounts can be taken for granted, on the other hand, specialist adapters (speed boosters, helicoid adapters, tilt/shift adapters) are not available for all mirrorless mounts, but daisy-chaining adapters (e.g. Minolta SR -> Canon EF; Canon EF –> mirrorless) can offer a work-around.

Using Minolta SR mount lenses on dSLRs is also be an option, but it is not trouble-free due to that the Minolta SR mount’s flange focal distance is shorter than that of any dSLR mount (technically with the exception of Olympus’ four thirds mount). Hence, any attempt at adapting Minolta SR lenses must rely on an adapter that uses corrective optics to allow infinity focus. However, such adapters are readily available.

History of Minolta

The company that would eventually develop into the Minolta that manufactured this lens was formed in 1928 as (Nichidoku Shashinki Shōten 日独写真機商店) – a company aiming to produce cameras in Japan using parts (especially shutter mechanisms) sourced from Germany. Initially, the company even employed German camera technicians. During its first years, the company launched several cameras combining locally produced with imported parts. In 1931 the company was renamed Molta Gōshi-gaisha (モルタ合資会社) ⁷ and soon thereafter the German technicians left the company. The contemporary name Minolta was first used for a camera model in 1933.

In 1937 the company changed its name to Chiyoda Kōgaku Seikō K.K. (千代田光学精工㈱, meaning Chiyoda Optics and Precision Industry Co., Ltd.), and continued to focus on camera manufacture until Japan’s increasing war footing led to the company increasingly focusing on the war effort. After the war Minolta quickly went back to camera manufacture, but as the company also absorbed what used to have been a navy optics manufacture, Minolta suddenly was well placed to produce cameras entirely in house. Hence, the early prewar years saw Minolta both producing TLR’s and folding cameras for medium format film, 35 mm viewfinder and rangefinder cameras, and 16 mm subminiature cameras.

1958 and the birth of the Minolta SLR

In 1958 Minolta introduced the SR-2 single-lens reflex camera. That camera was fairly advanced and utilised many of the technologies and approaches that we today expect from an SLR (pentaprism, instant return mirror, lever winding), but it also introduced a proprietary bayonet lens mount that allowed open-aperture composition and focusing (on compatible lenses). Spurred on by that success, the company in 1962 changed its name to Minolta Camera K.K.

While Minolta in the subsequent decades made many improvements and extensions to the Minolta SR mount, that mount remained fundamentally unchanged until the late 1990s (the last Minolta SR compatible body was introduced in 1995) in that Minolta managed to maintain full forwards and backwards compatibility (you can mount any 1958 Minolta SR lens on a 1995 Minolta X-370s and it would work just as on a 1958 SR-2). Knowing how much other makers (e.g. Nikon) struggled with this, that is not a minor accomplishment.

More details of the internal progression of the Minolta SR mount is given in the JAPB article on the Minolta SR mount.

1985 and Minolta as the forerunner of the AF revolution

In 1985 Minolta beat its entire field of rivals to the punch by introducing the Minolta 7000 AF ⁸ – the world’s first working autofocus SLR body, its attendant line of autofocus lenses, and a new lens mount (the Minolta A or ⍺ mount). In a move that angered anyone who had an investment in Minolta SR lenses ⁹, the new lens mount would not only be different, but also sported a flange focal distance longer than the Minolta SR mount, meaning that existing lenses could not be used at infinity without using an adapter with optics (which leads to both a mild deterioration of image quality as well as a mild teleconversion).

While Minolta still introduced a small number of Minolta SR mount compatible camera bodies after 1985, development of Minolta SR optics and bodies effectively ended as Minolta put all its brawn into making its AF bet a success.

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. ↩︎
7. ‘Molta’ was a contraction of “Mechanismus Optik und Linsen von Tashima” ( Engl: “Mechanism, Optics and Lenses by Tashima”), indicating that German influence in the company were still quite strong. ↩︎
8. Minolta is one of those companies that made a habit of naming products differently in different markets, and unless you’re aware of this, it will make your head spin. The Minolta 7000 AF would be called the Maxxum 7000 in the US, and the Alpha 7000 in Japan. More problematically, this would lead to some situations where very similar monikers would be used in different markets for wildly different cameras. Also, those lenses that would carry the name ROKKOR in the rest of the world would regularly be branded ROKKOR-X in the americas. ↩︎
9. Canon would do exactly the same two years later. ↩︎