| Author | Message | ||
     Ethostech Tinkerer Username: Ethostech Post Number: 149 Registered: 07-2006 Rating: N/A |
Here's a little background for the understanding of the contributors to date. The Werra is an exquisite design from early 1960's East Germany and initial models used the West German Synchro-Compur shutter. When political/commercial elements resulted in a supply cut-off, Zeiss Jena designed its own shutter - the RVS which is in fact the most accurate leaf shutter ever made. To all intents and purposes the nominal shutter speeds are in fact just what you get in practice. If you think you can hand-hold a 1/30 exposure - try it with any other leaf shutter and then try it with a Werra RVS - and the difference in picture negative sharpness will stagger you. And too at the top end, the 1/700 sec is stunningly on the ball. This was achieved by the pseudo rotary motion of the main shutter blades which unlike conventional leaf shutters do not open, come to a dead stop, and then reverse their direction to close. Those who study the design will realise that the shutter of such configuration is bound to open during the cocking action and thus expose the film-plane. Zeiss Jena overcame this by incorporating a second (capping) shutter at the film-plane. The latter would close during the cocking action. and then open immediately afterwards. Servicing of the Werra shutters can be a little tricky and is not a job for a novice tinkerer - but the main obstacle/difficulty being experienced with this 50 year old camera model is in removing the total lens-block which is in fact held by a slotted ring as on the outside periphery of the rear element. So one has to work through the film-plane to remove it. The capping shutter has to be accessed though the rear of the lens block - hence the need to remove from the camera body. The slotted ring is of brass and it screws into female aluminium alloy. Two of more than a dozen Werras which I have restored/rebuilt for my "Collection" - ended up as "junkers" because the aforesaid slotted ring was effectively "welded" by galvanic action of the dissimilar metals. I engineered a special tubular key with "tommy-bar" and with a stainless-steel precision-fit crosspiece to fit the ring-slots. I tried trckling a little acetone into the threaded area - and soaking to soften any possible "shellac: locking. And subsequently was driven a fabricate a very precise metal shield-mask to protect other than the slotted ring from a pencil-tip butane torch heat. Howver, nothing but nothing would break the stick of the slotted ring and ultimately the steel tubular key would predictably break away the shoulders of the brass slots. Of course there may be variations in the strengths of the Zeiss Jena Sumo Wrestlers who assembled the Werras . but regardless I have posted this little note to illustrate that not all things are "doable" with a 50 year old Werra, |