M 28/2.8 (version 2)

M 28/2.8 (version 2)

General Description

This lens is extremely interesting. Its lens mount is of the "original K-mount" type, and its name associates it undoubtedly with the M-series of K-mount lenses. On the other hand, the lens shares its most important characteristics with the later SMC-A lens: the linear aperture mechanism and the updated optical formula. Even the focusing ring is of the A-style.

Guesses can be made that in 1982 Pentax was already hard at work developing the A-series bodies and lenses, and when parts for the "original" M 28/2.8 lens were depleted, it was decided to switch to production of the new lens, but without exposing the externally visible A-series features — electrical contacts on the lens mount and "A" position on the aperture ring. Still, this lens with its low production numbers is a rather unique piece of K-mount history.

Product Information
Exact Name smc PENTAX-M 1:2.8 28mm
Color black
Year of Introduction 1982
Catalog Number 22977
Sold with Hood
Sold with Case dedicated hard case: exact name unknown

Technical Specifications

Optical Formula 7 elements in 7 groups
Aperture Range f/2.8 ~ f/22
Number of Aperture Blades 5
Minimum Focusing Distance 0.3 m
Maximum Magnification 0.13 X
Filter Diameter 49 mm
Maximum Diameter 63 mm
Length 37 mm
Weight 170 g
Cap plastic clip-on cap, 49 mm
Fitting Hood(s) clip-on hood: PH-S49
Fitting Case(s) dedicated hard case: exact name unknown