The collectors are after them because they form a unique little story in the development of compact cameras in the 50s and 60s. This is the story of half-frame 35mm cameras and the pursuit of these in the Japanese camera industry.
Olympus produced a series of these called Olympus Pen cameras over a couple of decades right into the 1980s. I like the Pen-D because it has one of the best lenses in the series, a 6-element F.Zuiko 32mm f/1.9, and, while having an uncoupled meter on board, it doesn't need batteries, especially those mercury ones from the early 60s, as the meter is a selenium type. The meter uses the EV system that I'm used to from my Minolta A5; very handy as you set the aperture and speed rings relatively for the light level and then you can turn then as one to choose the optimum speed and aperture for a particular shot without having to adjust the exposure again.
So I loaded a roll of KosmoFoto Mono 100 ISO film into it and had a go. 100 ISO is usually a good match for the aperture and speed settings on 1960s cameras and KosmoFoto Mono is one of my favourites anyway.
The F.Zuiko lens is way better spec than the 3-element lens on my Rollei B35, but the Pen only takes half-frames, ie half a standard 35mm negative, whereas the Rollei takes full 35mm frames. I wondered whether the better lens on the Olympus would overcome the lower film resolution of the smaller negatives.
Continuing the comparison with the Rollei, which was also an attempt at making a very compact camera shooting 35mm film, the Olympus is only a little bigger but much heavier and with a more robust feel to it. I had no worries that it would break when trying to load the film (see my post on the Rollei to see what the anxiety was with that one). The B35 is one of the most basic of the Rollei 35 line and so I suspect the more advanced ones would compare better. However, the Olympus lens won hands down and the little half-frame negatives a jewels of miniature art with high contrast and pin sharpness.
The only problem I have is that my nearly-60-year-old Pen-D has a stuck rewind release mechanism. When it comes time to rewind the exposed film back into the cassette, it won't. So I have to take the camera into the darkroom, open it and lift the film out past the sprocket wheels and then into the cassette or straight into the developing spiral. Not too much of a problem when you get 72 shots on a 36 shot cassette. So no frequent film changes and a blacked out change bag gets round that problem if required.
As with most of these tiny cameras, there is no focussing aid. Rangefinders and pentaprisms take up space. So the lens barrel is marked with the focussing distance in feet. However, this is where half-frame presents a real advantage. The standard lens for a full-frame 35mm camera has a focal length of between 45 and 55 mm. This little half-frame camera gets the same coverage of field and perspective with its much shorter 32mm lens.
Now focussing a camera without a rangefinder or the pentaprism of an SLR, requires making a good guess at the distance between the camera and the subject. This doesn't have to be exact though because of the phenomenon known as depth of field. When your camera is focussed on a scene there are some points in the scene which will be precisely in focus. These are the points that are exactly the distance indicated in the lens barrel from the plane of the film in the back of the camera. However there are other parts of the scene that are quite acceptably in focus, especially where they are at leas as sharp as the film grain will allow. These are close to the distance indicated in the lens barrel but not exactly there. How close they have to be is fixed by the depth of field. This depends on a relationship with the focal length of the lens (45 to 55mm for a full frame camera with a standard lens) and with the aperture setting (the f/number). The shorter the focal length, and the smaller the aperture, the deeper will be the depth of field and so the less precise the focussing needs to be.
On my full-frame Rollei there are markers on either side of the focus indicator to show the extent of depth of field with the aperture set at f/8 and f/16. So you can estimate how much leeway you have when focussing. Essentially this defines some focus zones when shooting in good light. The numbers on the barrel at 6 feet and at 20 feet are marked in red to show two of these zones: 20 ft for distance shots as the depth of field with the aperture at f/11 (the focal length of the lens divided by 11) or smaller will keep things in focus between 10ft and infinity there; and 6 ft for closeups, kept in focus between 4ft and 10ft.
Now the Olympus has a much shorter focal length and so deeper depth of field. It has stops on the focussing lever which you can feel engage at 4ft and at 10ft. These allow good focussing for close-ups and distance shots with the aperture set at f/8 or smaller. At bigger f/stops (f/5.6, f/4 etc) you still get away with a good guess at the distance but might have try three smaller zones rather than just these two.
One last thing: Olympus cameras always have count-down frame counters. I forgot this first time out and thought the counter wasn't working. So, if I load a 36 exposure film in my Pen-D, I have to reset the counter to 72 and it will count down my 72 half-frame pictures until it reaches 0 and I have to remove the film and develop it. A 24 shot cassette starts at 48 on the counter.
The best of the pictures from this test roll are on my Lomography Home.