Olympus Pen Cameras

 

Pen F
Following the success of the Pen, Pen EE and Pen D compact cameras, Maitani and Olympus turned their attention to a Single Lens Reflex camera, also in half-frame format. Launched in September 1963, the Pen F was at that time the smallest and lightest SLR camera readily available in the world. As with the original Pen, the design was innovative.

A porroprism mirror system eliminated the characteristic "hump" that houses the pentaprism in most other SLRs. Comprising two prisms and two mirrors the porroprism assembly could occupy the space "gained" by using the half-frame format beside the lens instead of above it.
The shutter was another idea to save space. A conventional SLR focal plane shutter would have resulted in the camera being almost as large as a full-frame 35mm, so Maitani designed a new shutter mechanism, calling it the Rotary Metal Focal Plane Shutter. After much testing he decided upon 0.003mm thick titanium sheet for the shutter blade, since no other materials had proved capable of withstanding the force and extremely high speed of the rotation - in the region of 80-90 feet per second! An additional advantage to the rotary shutter was that it would allow flash synchronisation at all speeds.
The result was a clean, compact camera with few "lumps" protruding from the body. The shutter speed dial was, unusually for an SLR, placed on the front of the body beside the lens whilst the flash synch socket was placed out of the way on the left-hand end of the camera. To save on the complexity of gears, the wind-on was a two stroke type. One stroke wound on the film and a second cocked the shutter.
As sold the Pen F was equipped with a 38mm/f1.8 lens, with a wide range of other lenses being available.

Since the Pen F had no meter built in, an accessory meter was available. Powered by a PX625 battery, it clipped on to the shutter speed dial locking to the speed selector. Thus, turning the meter dial changed the shutter speed on the camera. The CdS meter moved a needle over a scale on the top of the housing, indicating the aperture that should be set.

Pen FT
In 1966, the Pen F was replaced by the Pen FT, which had a built-in through-the-lens light meter and a self-timer. The wind-on was also upgraded with a single-stroke type.
The PX625 powered CdS meter was somewhat of a blessing in disguise. It was not coupled to the lens, so you had to read the setting off the meter in the viewfinder and transfer it to the lens aperture ring. It took 10% of the light that came through the lens, leaving only 90% to carry on to the viewfinder. Since the lenses were smaller than the equivalent full-frame SLR lenses, this made the viewfinder somewhat dark. The backlighting for the meter was a tiny window on the top plate of the camera, which was not particularly useful in low light.
The metering system itself was also innovative. Instead of giving the readings in f-stops it used a scale of 0-7, being relative aperture values based on the fully-open aperture. This was reckoned to be more accurate than traditional f-stops which take no account of light lost passing through a lens. It takes a little getting used to, but is simplicity itself - look up the number, dial it in and shoot.
This metering system required new lenses with the aperture values on the aperture control ring. Most lenses actually had both aperture value and f-stop values diametrically opposite on the outer ring, which could be pulled forward to disengage it from the inner ring, then rotated through 180 degrees and released to lock onto the inner ring again. At the time of changeover, Olympus did supply "conversion" kits - self-adhesive labels that could be attached to a Pen F lens aperture ring to make it usable on a Pen FT. It is also possible to use a Pen F lens on an FT, by metering with the lens stopped down manually.
The FT was available in chrome with black leatherette or all-black

Pen FV
Not everyone wanted a built-in meter or the reduced viewfinder brightness that it caused, so a version was produced without the meter, the Pen FV, which was quite literally a Pen FT with no meter. It was launched a couple of months after the FT and withdrawn in 1970, a year earlier than the FT. The Pen F accessory meter could also be used with the FV.
It was only available in chrome with black leatherette.

Medical Pen F/FT
The Pen F and FT models were also available with special viewfinders, focussing screens and various lens mount adapters for microscope and medical use. They are distinguished from their standard counterparts by the circular viewfinder masks, and have no specific markings on the body. The F Medical could be fitted with the Pen F accessory meter whilst the FT Medical could not. Although the FT Medical was not fitted with an internal meter, the meter illumination window and battery compartment were fitted, to reduce the number of components that needed to be manufactured.
The Pen F Medical was chrome with black leatherette whilst the FT was only available in black.

 

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Lenses
A wide range of lenses was made for the Pen SLRs, although not all were available in both the Pen F and Pen FT series, the latter requiring the aperture value scale to work with the Pen FTs meter. The Pen F lenses just had traditional F-stop numbers, whilst those for the FT had Olympus aperture value numbers and f-stop numbers on opposite sides of the aperture ring.

LENS	f-STOPS	ELEMENTS	GROUPS	ANGLE	FILTER	MINIMUM FOCUS
20mm	3.5-16	7	6	73	43	8"
25mm	2.8-18	7	5	62	43	10"
25mm	4.0-16	5	5	62	43	10"
38mm	1.8-16	6	5	43	43	14"
38mm	2.8-16	5	4	43	43	31"
38mm	3.5-22	5	4	43	43	6"
40mm	1.4-16	7	6	41	43	14"
42mm	1.2-16	8	6	39	49	14"
50-90mm	3.5-16	10	8	34-19	49	59" (5')
60mm	1.5-16	7	5	28	49	31"
70mm	2.0-22	6	5	24	43	31"
100mm	3.5-22	5	4	17	43	59" (5')
100-200mm	5.0-32	12	9	17-9	49	67" (6')
150mm	4.0-22	5	4	12	49	67" (6')
250mm	5.0-32	5	3	7	58	138" (12')
400mm	6.3-32	5	4	4	72	197" (16')
800mm	8.0	5	5	2	25.5	630" (52')

 

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Accessories
Apart from the cameras and lenses the Pen SLR range was a system, with accessories to cover just about anything a photographer might require, including;

Accessory Shoes - clipping onto the viewfinder surround providing a "cold" flash mount shoe

Viewfinder Magnifier - clipping onto the viewfinder surround, this protruded about 3" straight out behind the camera and magnified the middle of the viewfinder image

Right-Angle Viewfinders - clipping onto the viewfinder surround, this magnified the centre of the viewfinder image and could be rotated to allow viewing from above, below or to either side of the camera. It could be used at any rotation angle but click-stops were provided at the 90-degree positions.

Extension Tubes - used to stand the lens out from the camera lens mount and increase the lens-film distance, thereby reducing the minimum focussing distance to allow greater magnification for close-up work. The set comprised a body mount, a lens mount and screw-in tubes to set the spacing, and stopped the aperture down to the setting on the aperture ring control.

Lens Reversing Mount - comprising two parts this allowed the standard 38mm lens to be reversed on the camera for extreme close-up work. One part fitted onto the camera lens mount and had a circular clamp to grip the front of the lens barrel whilst the other fitted onto the lens mount and stopped the aperture down to the setting on the aperture ring control.

Focussing Rail - could be mounted on a tripod with the camera mounted to it for fine focus control.

Pen-Up 3 Copy Stand - used to mount the camera a fixed distance above documents for copying.

Bellows - could be used to move the lens plane of focus allowing extreme close-up work.

Slide Copier - used in conjunction with the Bellows unit and standard 38mm lens.

The Bellows and Slide Copier were made in two versions, the first only fitting the Pen F. With the introduction of the Pen FT came the Bellows 2 and Slide Copier 2 which had increased spacing from the body to clear the FTs self-timer lever.

The most useful accessories were the Mount Adapters, which allowed a wide range of lenses from other cameras to be used on a Pen SLR. Adapters were made for Canon, Nikon, Exacta, Minolta, Pentax (M42 screw) and Leica 39mm mounts as well as, not surprisingly, Olympus OM. None of them had automatic aperture control, so it was essential that any lens used had a means of stopping the aperture down manually. The Olympus Zuiko OM-series lenses were perfect for this, having a depth-of-field preview stopdown button on the lens - as did many of the M42 screwmount lenses. Some were also made by other manufacturers to cater for other lens mounts, eg Pentax PK and T-Mount