Matt Blaze
5-Jan-2008, 16:05
In recent thread (http://www.largeformatphotography.info/forum/showthread.php?t=31200), someone posted a link to this Sinar lens guide (http://www.sinar.ch/file_uploads/bibliothek/k_87_UserInstructions/155_0_sinarlensesforlargeformatphotography.pdf).
I must admit it left me confused as to the difference between the DB and DBM mounts. In this guide, only the 300mm and 360mm lenses are listed as being available in DBM, with the others available in DB. For example, the -S 240mm is listed as being available in a DB mount, not a DBM mount. But I have an -S 240mm in what I thought was a DBM mount. It has an aperture ring with a red unlock button that lets me stop the lens down without any external shutter control.
I now realize I might be confused as to the difference between the two mounts. I had thought that the difference was that DB has no manual aperture override ring, while DBM has the ring with the red button. Is that, as I now suspect, wrong?
This is an important distinction for me. I have a scanning back and no external Sinar shutter or aperture control. I can use shutterless lenses with this arrangement only if they have an aperture override ring. Since the DB and DBM lenses are often rather inexpensive on the used marked compared with the same lens with a Copal shutter, being able to use them when possible is nice.
So, what actually is the difference between a DB and a DBM mount?
Thanks
-matt
I must admit it left me confused as to the difference between the DB and DBM mounts. In this guide, only the 300mm and 360mm lenses are listed as being available in DBM, with the others available in DB. For example, the -S 240mm is listed as being available in a DB mount, not a DBM mount. But I have an -S 240mm in what I thought was a DBM mount. It has an aperture ring with a red unlock button that lets me stop the lens down without any external shutter control.
I now realize I might be confused as to the difference between the two mounts. I had thought that the difference was that DB has no manual aperture override ring, while DBM has the ring with the red button. Is that, as I now suspect, wrong?
This is an important distinction for me. I have a scanning back and no external Sinar shutter or aperture control. I can use shutterless lenses with this arrangement only if they have an aperture override ring. Since the DB and DBM lenses are often rather inexpensive on the used marked compared with the same lens with a Copal shutter, being able to use them when possible is nice.
So, what actually is the difference between a DB and a DBM mount?
Thanks
-matt