First, the film is wound, bringing the reflex mirror into place at the same time. The aperture is then opened to its widest setting to give the brightest image on the screen. To do this, the photographer first has to press in a small catch on the aperture setting ring, keeping it depressed as the ring is turned against the tension of a spring. All the time this catch is depressed, the spring pulls the setting ring back toward the smallest aperture, but with the aperture at its widest setting, the catch is released and the ring locks into place.

From the rear with the eye-level viewfinder in place.

As the aperture ring reaches its widest setting a quiet click indicates that a small lever beneath the lens has been moved very slightly to one side, allowing a pin to spring out from the body and block its return. Now, when the f/stop required for taking the picture is reset on the control ring around the lens, the actual aperture remains wide-open for easier focusing. As the picture is taken, however, first pressure on the shutter release retracts the pin, allowing the lever to move back and causing the aperture setting to spring to its preset aperture, just before the mirror flips up and the shutter fires. It then remains at this smaller aperture setting until the whole sequence is repeated for the next picture.

The shutter is not a focal plane type that you would expect in most 35mm SLRs. It is a Prontor with X and M synchronization for electronic and bulb flash respectively, using an iris, set into the camera body, behind the lens. As the film is wound, the mirror is lowered and the iris opens to bring an image to the viewfinder, while the lowered mirror blocks light from the film. As the exposure is made, the mirror springs up and the iris closes, between them giving the required shutter speed.

The lens is interchangeable with a bayonet fitting, released by moving a small lever below the lens from a five o'clock setting to seven o'clock. The Mecaflex is usually found with a 40mm f/3.5 Kilar lens, but sometimes with the rarer 40mm f/2.8 Kilar and, if you are very lucky, with the even rarer 105mm f/4 Tele-Kilar. Extension tubes were also available.

The very rare lizard skin version, fitted with the telephoto lens.

With a few exceptions, single lens reflexes of the early '50s were mostly built with waist-level, rather than eye-level, viewfinders and the Mecaflex was no exception. It was, however, unusual in offering a now very rare accessory viewfinder that fit over the ground-glass screen to convert the camera for eye-level viewing.

This is little more than a small metal box which is pushed into the hood to rest on top of the focusing screen. Inside is an angled mirror and set into one side is a lens in an eyepiece. It doesn't attempt to correct the laterally reversed image on the screen the way a penta-prism would and if the camera is held vertically, the image turns upside down as with any waist-level reflex. The resulting image is dim but adequate when the light is bright.

Today's value is around $1500 for the chrome and black camera with standard lens, more like $2000-$2500 for the lizard skin version, and around $750 extra for the tele lens, if you can get one on its own. I've only ever seen them for sale with the camera and a seller reluctant to part them.