A system of photography pioneered by OLYMPUS (Tokyo, Japan) which used standard rolls of 35mm film, but put two exposures on each 35mm frame. The negative size of 35mm is 24x36mm. Half frame is 24x18mm. As a result, the cameras were much smaller (their compact design eliminated the usual SLR protruding prism), much lighter and easier to handle. Also, half-frame was closer to the 8x10, 16x20 proportions (whether horizontal or vertical) and required little cropping. Enlargements of half-frame usually required only about 25% more enlargement than full frame.
THE CAMERAS:
- Pen F - basic SLR with rotary metal focal plane shutter with speeds ranging from 1 to 1/500th of a second, horizontal quick return mirror, porroprism viewfinder, and a proprietary bayonet mount for interchangeable lenses. Can be easily recognized by the big golden gothic letter F engraved on the front plate.
- Pen FT - model with a built-in Through-The-Lens (TTL) uncoupled open-aperture CdS exposure meter, new type shutter, and a self-timer;
- Pen FV - as the FT, but without the exposure meter (optional clip-on meter was available).
THE LENSES:
OLYMPUS offered a complete line of high quality interchangeable lenses for the Pen F, FT and FV cameras. They were designed in keeping with the concept of lightness of weight, compactness of size and reliability in operation that characterized all the components of the OLYMPUS Pen F system.
All OLYMPUS Pen FT lenses were calibrated in both conventional f/stops and the unique OLYMPUS TTL numbering system. The TTL numbers were relative aperture values based upon "open aperture" light measurement as used in the operation of the FT metering system. The incorporation of the conventional f/stop calibrations insured the workability of the OLYMPUS interchangeable lenses with conventional light metering systems such as that employed on the Pen F and FV cameras, or with a hand-held meter.
NOTE: Due to the maximum format (24x18mm) and short flange focal distance (28.95mm), OLYMPUS lenses for Pen F series SLR cameras can only be adapted to APS-C mirrorless cameras.