View Full Version : disassembling Zeiss (or Docter Optic) 750 f9 Apo-Germinar barrel lens?

John Schneider
13-Nov-2012, 15:42
Has anyone disassembled one of these barrel lenses? I have one (a CZ-Jena example) and I'd love to mount it in a shutter and save a whole bunch of weight. I've gently tried some strap wrenches but before I do any more, I wanted to see if anyone had experience disassembling this wonderful monster. Thanks!

CP Goerz
13-Nov-2012, 15:54
From my personal experience only I say...these things always end badly and expensive. :-)


Dan Fromm
13-Nov-2012, 16:56
John, the only shutters that will come close to giving full aperture with a 750/9 are Compound and Ilex #5s. For SKGrimes' take on y'r problem, see http://www.skgrimes.com/lens-mounting/table-of-lenses-fitted-to-shutters

If you ask Adam, if he knows I expect he'll tell you whether your lens' cells are direct fits in any shutter. There's no guarantee that he knows.

According to Arne Croell (see http://www.skgrimes.com/lens-mounting/table-of-lenses-fitted-to-shutters) CZJ Apo-Germinars were sold only in barrel. There's no guarantee that any CZJ Apo-Germinar's cells are direct fits in any shutter. Docter (see http://www.arnecroell.com/docter.pdf) offered the 750 at f/9 in barrel and at f/11.5 in a Copal #3 but there's no guaranteed that the Docter version is mechanically the same as the CZJ or that the two Docter versions' cells are the same mechanically.

As Andrew wrote, what you want to do isn't a job for an amateur.

If I were you I'd have an adapter made to allow a #5 (Compound or Ilex, Ilex 5s are less expensive and easier to find) to be hung on the front of the lens. I have such an adapter that holds a Compound #5 in front of a 900/10 Apo-Saphir.

14-Nov-2012, 01:56
I have a vague memory that mine came apart fairly easily. As Dan says though, you'll likely be looking at a custom machining job into a #5 shutter. I believe SK Grimes have done this successfully before.

If you'd rather use a #3 shutter it would probably be more practical to sell the APO-Germinar and pick up an APO-Artar of the same focal length which is much smaller/lighter. Will still lose some aperture being fitted to a Copal #3 but it makes more sense in use.