Thursday, February 7, 2008

Link of Lenses in Ochotta Cameras

I am familiar with the lens linking done by RBT and also by the service center used by 3D Concepts. The links in the lenses of the Yashica stereo cameras, built by Fritz Ochotta, is different. It is simpler and in my opinion very effective. As you can see from the pictures above, each lens is fitted with a metal ring. The ring is secured with screws at the top and bottom. At the top there is piece with a round end. A metal link is connecting the two balls.

This system is really simple and it works well. It is easy to adjust. You can easily remove the link bars and put them back in place. You can even remove the entire system and restore the lens to its original state (note: the rubber focusing rings have been removed from the lenses).

Depending on the focusing range of the lenses, it is quite possible that the link imposes a minimum focusing. In the 85mm lenses I can remove the bar, turn the lenses to close focusing, and then re-attach the bar, this time at the bottom.

As it turns out, these contax lenses are well matched so the aperture linking links the same apertures in each lens. Are the links needed? For a wide angle lens (say, 28mm or wider), one can get along without links. Just remember to put the same aperture in each lens and focus near infinity. For longer lenses, focusing is more critical so I think it is important to link the focusing. The aperture linking is a matter of convenience and it protects you from accidentally changing the aperture in one lens only, and ending up with different exposures.

I would like to be able to link other pairs of lenses so I am looking for help in getting the materials required to create more links.

1 comment:

Anonymous said...

Dear Dr. T.,

As I also bougth a (very likely) Ochotta some days ago, I have the link on the table. It looks like the rods modelists use to act the rudders and flaps in model planes and model ships. Therefore I presume you will get more links in a shop for radio-controlled models, at least here in Germany.

Kind regards

Martin Meitzner