Pekka Buttler (5/2025)
Olympus Pen F mount specifications and identification
Mount type: Bayonet (lens release on lens)
Flange focal distance: 28,95 mm
Film format: 18mm x 24mm (‘Half frame’)
Mount communication: Aperture stop-down (camera-to-lens); Selected aperture (lens-to-camera)
[1] Three-pronged bayonet with tapered prongs
[2] Aperture stop-down lever
[3] Lens release button
[4] Locking pin is hidden under bayonet prong here (at 01:30)
[5] Aperture stop-down button (for depth-of-field preview).
Basic Information on the Olympus Pen F mount:
The Olympus Pen F camera was introduced in 1963. It was an interchangeable lens half–frame (18×24 mm) system camera building on the success of Olympus’ previous line of (fixed lens) half-frame cameras (PEN, PEN-S, PEN-D and PEN EE).
The Pen F line was not just a compact system for making portrait snaps. Instead it offered a wide range of lenses from 20 mm (28 mm full-frame equivalent) wide-angles to some rather crazy 800 mm (1150 mm full-frame equivalent) tele lenses.
The Pen F camera (1963–1966) was later modernised to the Pen FT (1966–1972) and Pen FV (1967–1970). After the 1972 introduction of the OM system, the Pen F system was discontinued (but Olympus continued manufacturing various fixed-lens variants of the PEN series into the 1980s).
The Olympus Pen F system can be said to – in several ways – have laid the groundwork for Olympus’ subsequent success with the OM system, and many of the Pen F system’s lenses have enduring reputations.
Adapting Olympus Pen F lenses
If you have a functional Olympus Pen F (OR FT or FV) camera body I recommend you put some film into it to get the experience of using the lenses in their original intended environment.
Due to the short flange focal distance (28,95 mm) and the smaller image circle of the Olympus Pen F mount Olympus Pen F lenses cannot be adapted to any brand of SLR or dSLR.
On the other hand, should you intend to adapt Olympus Pen F lenses to mirrorless cameras, the flange focal distance is not an issue. Rather, the smaller than full-frame image circle means that you might be best served using an APS-C sized sensor (or using your full-frame sensor in crop mode. As of this writing, Pen F adapters exist for basically all mainstream mirrorless mounts.
Footnotes:
1 The OM system was originally named the M-system (after the head designer Yoshihisa Maitani), but Leica (producers of the successful M-series of rangefinder cameras) opposed this naming. As Olympus was very much interested in western markets, the system was quickly renamed OM (‘Olympus Maitani’), but early OM-series bodies (M-1) and lenses can be found and are of special interest to collectors)