Data sheet: Nikkor Ai 28 mm f/2.8

Pekka Buttler, 08/2022 (updated 03/2023)


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

Brand:Nikon (Nikkor)Lens name28 mm 1:2.8
Focal length(s)128 mmAngle-of-view274°
Maximum Aperturef/2.8In Production1977–1981
Lens mountNikon FSubfamily (if applicable)Ai (Automatic indexing)
Length344,5 mmDiameter463,5 mm
Filter ring diameter52 mmWeight241
Lens element count7Lens group count7
Aperture blades (S/R/C)57 SFocus throw190 °
Minimum focusing distance30 cmsMaximum magnification1:7,5
Has manual aperture ringYESHas Manual focus ringYES

Further notes:
• While similar-spec Nikkor Ai and Ai-s lenses in most cases are very similar, this is one of the exceptions, as the later Nikkor Ai-s 28 mm f/2.8 (data sheet here) is a redesigned version with higher element count and CRC.

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.
• 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) 6
• 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.

The table below

While Nikon has a long history of producing 28 mm f/3.5 lenses (starting in 1960), and has produced 28 mm f/2 lenses since 1970, the intermediate f/2.8 version was first introduced in 1974 (as a new Nikkor lens). The development of Nikkor’s 28 mm f/2.8 designs is summarised in the table below:

yearsSeriesoptical constructionaperture bladesMFDnotes, links
1974–1977K7 elements in 7 groups7, straight0,3 mPre-Ai, rubber focus ring
1977–1981Ai7 elements in 7 groups7, straight0,3 m[this lens]
1979–1981series E5 elements in 5 groups7, straight0,3 mall-black design
1981–1985series E5 elements in 5 groups7, straight0,3 msilver-ring design
[data sheet]
1981–2020Ai-s8 elements in 8 groups7, straight0,2 mCRC
[data sheet]
1986–1990AF5 elements in 5 groups7, straight0,3 mplastic focus ring
1990–1994AF new5 elements in 5 groups7, straight0,3 mrubber focus ring
1994–2020AF-D6 elements in 6 groups7, straight0,25 m[data sheet]


Besides adapting, this lens can be used natively on all current high-end Nikon dSLRs and several earlier medium-to-high-end older Nikon dSLRs7. 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.


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 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.

7 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