I have questions regarding the Sinar DB mounting system, with which I'm unfamiliar.

Does it make sense to have a 75mm f8 Super Angulon mounted on a Sinar DB system? How about a 75mm f5.6 Super Angulon? (If not, why not.)

If I'm correct, the Sinar DB system is for use with the Sinar shutter mechanism that one can purchase with the Sinar P. Is this true?

Both the 75mm f8 SA and the 75mm F5.6 SA mount on a Copal or Compur number "0" lens.

QUESTION: Does the choice of DB mount for a particular lens depend only on the mounting diameter for the front and rear elements of that lens, or does it depend also on the focal length?

For example, a Symmar-S 150mm lens also requires a Compur or Copal number "0" shutter, but the f-stops are spaced differently for the 150mm than for either of the 75mm lenses.

If the choice of DB mount also depends on focal length, is there identification on the DB mount that allows one to verify that it's the correct mount for a 75mm SA?

-- neil poulsen (neil.fg@att.net), March 26, 2001

Answers

The DB mount must allow for the exact same placement as the lens would be if in a shutter, but also placing the rear portion of the lens away from the sinar shutter. the main advantage of course is one shutter instead of a shutter for each lens, meaning that you will only have one set of variations from actual marked speeds. Every DB mount is made for a specific lens. You can get that list by getting ahold of a sinar catolog from Sinar USA. Kevin

-- Kevin Kolosky (kjkolosky@kjkolosky.com), March 26, 2001.