Rietzschel Kosmo Clack stereo camera for stereo images roughly 45 x 55mm each on a glass plate, or Vest Pocket roll film (127) if used with the appropriate roll film back. The camera would also make single wide angle exposures using a neat mechanical system whereby the lensboard was slid sideways, centering one lens over the plate and retracting the septum (internal divider), see image 3 on the right. Rietzschel cameras were made in Munich Germany, starting at the beginning of the 20th century around 1900. Mostly known for good quality folding bed cameras typified by the Pre World War 1 Heli Clack. Stereo photography was popular around this time and Rietzschel produced this quite exceptional Kosmo Clack around 1914 according to multiple references. Unfortunately quite short lived as the war started that year and production doesn't seem to have resumed at the end of hostilities in 1919. Rietzschel itself survived the war and production of Heli Clacks amongst others continued until taken over by Agfa around 1925. Agfa kept some of the models for a few years until phasing them out until only the name "Clack" survived in use on a number of unrelated Agfa models into the 1950s. The Kosmo Clack is a beautifully engineered camera whose central core is a single piece cast zinc box. The casting was then extensively machined externally with the focus rack strut slots, mating faces and other niceties cut into it. The lensboard is mainly machined from solid cast zinc block, this slides sideways on a zinc plate base with nickel plated brass insert. A limited degree of lens rise is supplied by a brass assembly that slides upward mounted in the lensboard. This brass assembly is coated with black vitreous enamel, judging from the hard brittle finish. The Stereo Compur shutter mechanism, supplied by F. Deckle, was mounted on the front of this panel and was easily removable by releasing a lock and pushing the shutters upwards against a firm spring. Internally the film chamber was divided by a cloth septum to prevent left and right images overlapping. The mechanism included a spring roller to allow it to stretch to one side when used as a wide angle camera, extend when focussing and supply tension for the over centre retraction. Most descriptions say "panoramic", but with an angle of around 80deg at infinity using the 6.5cm focal length, this seems a tad generous to me. I suspect this feature was aimed more at widening the view when used in 13cm focal length form. Composing the image was achieved using the pop up waist level finder mounted on top,some having a graticule etched to help align horizontals, some examples have an eye level back sight instead, these seem to be earlier. Alternatively a ground glass screen could be mounted in the dark slide rails for use on a tripod. Three eighths inch tripod bushes were supplied for both horizontal and vertical planes as were spirit levels. If that wasn't enough, the camera could be focussed, unlike it's more popular, and heavier, Jules Verascope competitor. The lensboard could be run out using twin rack and pinion drives to ensure the lensboard remained parallel, revealing finely pleated rectangular section natural leather bellows with chamfered corners. Lastly, by unscrewing the rear group of the lens, the front group could be used alone, doubling the focal length to 13cm. The camera could also be used as a stereo viewer by inserting an optional double eyepiece in place of the taking lenses. Initially it was thought to be cast aluminium, which would have made it a very early example of this technique, but during a total strip down it was discovered to be a zinc alloy. The castings are very good for the era this example having but two visible voids in the casting and one of those is hidden beneath the leather covering.

Cast zinc alloy was a relative novelty when the Kosmo Clack was made. Rietzschel resorted to considerable post cast machining to get this ambitious single piece casting usable, almost every external surface needing to be milled or polished. This image shows the main body separated from every component during the deep clean it received in October 2023. These zinc castings are long lasting but not inert and do oxidize, a dark grey film forming over unfinished or irregularly handled surfaces. As the material is porous to air, oxidation can pass through it. This part needed all the matt black paint removing as it had broken down and was flaking off, rendering the camera unusable - a common failing as some paints are reluctant to form strong adhesion to zinc alloys. This image was made during the Kosmo Clack's deep clean, partially documented in Project 16.

When configured for wide angle images the internal septum retracts to one side allowing the entire plate to be used, this view in the back shows the septum retracted. In theory the camera could be used with or without the rear element removed. It's likely that in 6.5cm focal length form there would be considerable, likely unacceptable, vignetting and loss of focus towards the edges of the frame. Both these undesirable faults wouldn't be so noticeable with the focal length doubled to 13cm but the exposure required would need to be in the order of four times longer for any given aperture. In due course the intention is to test this out.

View other viewfinder cameras in this collection.

Body No. 101590S
Shutter, Stereo Compur, serial No.562366, speeds 1, 2, 5, 10, 25, 50, 100 and 250th
Lens, 2 x Rietzschel Doppel Anastigmat 65mm f/6.3, left serial 94591, right 94592
Condition, 5F