Archived posting to the Leica Users Group, 2001/11/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In a message dated 11/28/01 11:10:08 AM Eastern Standard Time, eric.calderwood@btinternet.com writes: > I have this DR-Summicron which has its aperture scale and index directly > > opposite to the distance scale. When mounted on the camera, the distance > > index is facing up and the aperture index and scale is facing down. > > > > Is there a way to rectify this? > > > > Dan K, Dan: All of the DR and Rigid Summicrons were matched to individual focussing mounts when delivered new from the factory. The likelihood is that your Summicron lens head - the front optical part of your lens - has been mated to a different focussing mount than the one originally furnished with the lens when new. All DR Summicrons had (and have) an exact focal length of 51.9 mm. The Rigid Summicrons produced at the same time had exact foacl lengths that may have been 51.9 but that could have varied with an indivual specimen. Unscrew the lenshead from your DR and look for two digits inscribed on the blackened back part of the barrel. If your lens was really a DR at birth, the digits must be "19". Leitz dropped the first digit, i.e. 51.9 = 19. The digits could be anything from 99 (meaning that with the dropped digit, that lens would have an exact focal length of 49.9mm) or 23 (meaning that the focal length is 52.3). I'm not stating limits at either end, simply giving examples. It is entirely possible that you have a Rigid Summicron lens head of a focal length other than 51.9 and that someone has improperly mated it to a DR focussing mount. Or it may be the correct 51.9 but the lens head has not been properly calibrated to the focussing mount. That would not have happened at the factory. Alternatively, if the lens head is 51.9mm, it is possible that the original focussing mount was damaged and someone found a replacement that has not been properly adjusted. My Rigid 50/2 Summicron happens to be 51.9mm. Last year, I contacted Don Goldberg of DAG to ask if he might have a DR focussing mount I could use with the Rigid lens head. He sent me one (since it was a DR focussing mount, it's automatically 51.9). It turned out that when screwing the lens head in, the aperture scale was off about 90 degrees to the left of top dead center, making it awkward to use. Don said he could adjust the lens head to work, but that meant that when used on the Rigid focussing mount, the aperture scale would be off 90 degrees in the other direction. I had to send it back. Sorry this has been so long but if you're not familiar with the lenses, it needs careful explanation. Good luck. Seth La k9 - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html