Data Sheet: Nikkor Ai-s 50 mm f/1.2

Pekka Buttler, 08/2022

Specifications

The table below summarizes the lens’ key specifications:

Brand:	Nikon (Nikkor)	Lens name	Nikkor 50 mm 1:1.2
Focal length 1	50 mm	Angle-of-view 2	46 °
Maximum Aperture	f/1.2	In Production	1981–2020
Lens mount	Nikon F	Subfamily (if applicable)	Ai-s
Length 3	47,4 mm	Diameter 4	68,4 mm
Filter ring diameter	52 mm	Weight	370 grams
Lens element count	7	Lens group count	6
Aperture blades (S/R/C) 5	9 S	Focus throw	110 °
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	1.2•2-2.8-4-5.6-8-11-16

Further notes:
• This lens is Nikon’s last superfast fifty for the Nikon-F mount
• It was originally introduced in 1981 but stayed in production until 2020 during which time ≈167 000 copies were made.
• The Ai-s version replaced the earlier Ai version (manufactured 1977–1981), bringing two more aperture blades (the Ai-s had 9 straight blades while the Ai had 7 somewhat rounded blades), a significantly shortened focus throw and minor weight savings.
• Nikon offered two different dedicated, thread mounted hoods; the steel HS-12 hood and the rubber HR-2.

A brief genealogy of Nikon SLR lens types

Nikon is undoubtedly one of the great names in 35 mm SLR photography. The Nikon F mount has been in continuous production since 1959. During that time, the mount has developed/changed in some detail, however without ever fully sacrificing compatibility.

In short (a longer version is here), the development of Nikon’s SLR lenses can be traced as follows:
• 1959–1977: Pre-Ai. Manual focus lenses that use ‘rabbit ears’ to communicate selected aperture with the camera body. Pre-Ai lenses can further be subdivided into
• F-type (1959–early 1970s: metal focus ring and single-coated),
• C-type (early 1970s–mid 1970s: metal focus ring and multicoated), and
• K-type (mid 1970s to 1977: rubber focus ring and multicoated).
A significant share of remaining Pre-Ai lenses have since been converted to Ai-spec (Ai’d)
• 1977–1986: Ai and Ai-s. Manual focus lenses that may have ‘rabbit ears’ for backward compatibility, but are designed to communicate selected aperture with the camera body through indentations in base of aperture control ring.
• 1986–today: AF and AF-D. Autofocus lenses that do not have a focusing motor within the lens, but rely on the focus motor within the camera. All AF and AF-D lenses are simultaneously Ai-s lenses (they are Ai-s lenses extended with AF) ⁷
• 1996–today AF-S and AF-P. Autofocus lenses that have an internal focusing motor and do not rely on the body having a focusing motor.

Nikon offered a superfast fifty for the F-mount from 1965 to 2020. A short rundown of Nikon’s F-mount super fast fifties is given below:
• 1965–1967 55 mm f/1.2 (7 elements in 5 groups, 7 blades, 0,6 m MFD, “Nippon Kogaku”) (F-type)
• 1967–1972 55 mm f/1.2 (7 elements in 5 groups, 7 blades, 0,6 m MFD, “Nikon”) (F-type)
• 1972–1974 55 mm f/1.2 (7 elements in 5 groups, 7 blades, 0,6 m MFD) (C-type) [data sheet]
• 1974–1977 55 mm f/1.2 (7 elements in 5 groups, 7 blades, 0,5 m MFD) (K-type)
• 1977–1978 55 mm f/1.2 (7 elements in 5 groups, 7 blades, 0,5 m MFD) (Ai)
• 1978–1981 50 mm f/1.2 (7 elements in 6 groups, 7 blades, 0,5 m MFD) (Ai)
• 1981–2020 50 mm f/1.2 (7 elements in 6 groups, 9 blades, 0,5 m MFD) (Ai-s)

Further Nikon offered another, specialized superfast fifty during 1977–1998: The legendary 58 mm f/1.2 Noct–Nikkor (featuring hand-ground, aspherical lens elements to help combat spherical aberration, coma and astigmatism). The Noct-Nikkor was always a specialty lens and was pricey even while in production, but lately they’ve become collectors’ items and cost about 10 times that of an equivalent-condition 50/1.2…

Adapting

Besides adapting, this lens can be used natively on all current high-end Nikon dSLRs and several earlier medium-to-high-end older Nikon dSLRs ⁸. Likewise, if it still has its rabbit ears, it can be natively used on all Nikon F-mount film cameras ever produced (without the rabbit ears, it is limited to post 1977 bodies).

Thanks to being a fully manual lens (manual aperture, manual focus), the lens can be adapted to all mirrorless cameras using a suitable dumb adapter (and such adapters are easy to find). Moreover, a large range of special adapters (helicoid adapters, tilt/shift adapters, speed boosters) for using Nikon F lenses on most mirrorless systems are available.

Using Nikon F lenses on non-Nikon SLRs and dSLRs is likewise a distinct possibility. Thanks to the relatively generous flange focal distance of the Nikon F mount (46,5 mm), adapter rings for all dSLR mounts are available as well as for a goodly portion of film-era SLR mounts. Such rings may not allow for auto aperture, but even then the lenses can be used in stop-down metering mode.

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 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. There is a further sub-class of AF-D lenses called AF-I lenses that are otherwise AF-D lenses (meaning, fully Ai-s compatible), but have an internal focus motor. Only long tele lenses were made in AF-I variants. ↩︎
8. As of this writing, the following Nikon dSLRs fully support Aperture priority and manual metered modes on Nikkor Ai lenses: D2, D3, D4, D5, D6, D200, D300, D300s, D500, D600, D610, D700, D750, D780, D800, D800E, D810, D850, D7000, D7100, D7200 ↩︎