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Prewar Contax Collectors guide, part II

Zeiss bumps and the Contax shutter

The most interesting technical feature of the Contax camera is its shutter. It has brass curtain curtains that won’t burn if you accidently leave the camera on its back with the lens pointed at the sun. (Something you don’t want to do with a prewar Leica!) It has a lot of clockwork gears to move things around. And escapements to regulate time. In use it whirs, whizzes and clicks and it is surprisingly robust for all its complexity.

However the largest single drawback of the Contax is that very same shutter It was designed to be serviced at regular intervals. The many gears and shafts need to be oiled and the ribbons that open and close the curtains replaced. This need for service is particularly true of the shutter curtain ribbons. They were considered expendable, just like the camshaft timing belt on your car’s engine and the ribbons on a Contax will eventually wear out over time do to age and wear.

If a timing belt breaks on you car the results can be catastrophic for the engine. Fortunately for the Contax this is not the case. When the curtain ribbons fail, the camera is designed to take this event in good stride. Naturally it will stop working since there’s nothing to pull the curtains open and shut, and the shutter curtains will generally stick wide open after you’ve tried to one last time to rewind and fire the camera. However it’s not hopelessly broken. So relax and don’t get terribly upset if this fate befalls you. You’re not the first and certainly not the last photographer who’s experienced that.

One of my friends calls this a “Contax hibernation phase”. That’s because 90% of the cameras you’re ever likely to find are like that. Often they’re put into a drawer or back of a cabinet and eventually forgotten. Many stay there for decades until one day they’re resurrected, serviced and put back to use. If you see ever see a mint example of a Contax II or III, you can be sure that it spent quite a bit of time safely protected from the ravages of time and use while taking a drawer nap.

Probably the most important thing about this hibernation is that it’s taken in an environment that’s relatively favorable to the camera. Not too hot, not too cold and certainly not too moist or humid. If you come across a camera with large pronounced “Zeiss bumps” this is a clear indication that storage conditions were too moist. Leather will absorb moisture and this in turn creates conditions that allow the chemicals contained in the leather & shellac based glue to initiate an electrolytic reaction in the brass rivets and screws mounted in the aluminum body beneath the leather. (To put it simply, the brass bits below the leather turn green and the accumulation of this green corrosion pushes the leather up to create a blister known as a “Zeiss bump”.)

If you come across a camera with very large or excessive amounts of bumps it’s probably a good idea to pass it up if especially if you have other options or choices. The bumps indicate that it was stored in humid conditions and there’s a good chance that inside the camera, the shutter may have suffered as well. A camera with oxidized or rusted gears, shafts and bearing hidden inside of it is never a good deal. Though not impossible to service, it can be difficult and expensive to get them functioning again. Even if it is successfully put back into service, the shutter may still remain relatively stiff to operate.

The bottom line is buy the best camera you can find. You’ll have more pleasure with it and in the long run it will much be easier to sell if you ever decide to do so.