Archived posting to the Leica Users Group, 2004/12/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Here is a link to an example: http://www.saganich.com/Uneven.htm Chris Saganich -----Original Message----- From: lug-bounces+saganicc=mskcc.org@leica-users.org [mailto:lug-bounces+saganicc=mskcc.org@leica-users.org] On Behalf Of Saganich, Christopher/Medical Physics Sent: Wednesday, December 08, 2004 11:07 AM To: Leica Users Group Subject: RE: [Leica] Problem summicron uniformity Don, Thanks, I'll follow your procedure and see what happens. I was betting on the lens but after testing with another lens with similar results I'm thinking the shutter is off. Back to NJ then. Chris Saganich -----Original Message----- From: lug-bounces+saganicc=mskcc.org@leica-users.org [mailto:lug-bounces+saganicc=mskcc.org@leica-users.org] On Behalf Of Don Dory Sent: Wednesday, December 08, 2004 7:45 AM To: 'Leica Users Group' Subject: RE: [Leica] Problem summicron uniformity Chris, The most probable cause of the side to side unevenness is your shutter capping at higher speeds. To test this, open up your camera with the lens off pointing the camera at an even light source. Start tripping the shutter at say, 1/60, and work up to 1/1000. If all is well then you will see an even band of light. If all is not well then you will see an uneven opening as you describe in your post. A good CLA will fix this. On the other hand, if the ASPH has had a really good knock and one of the elements is out of alignment then you can get some strange effects including uneven lighting of the frame. What you describe would be almost impossible to occur, but almost is not not. Last, in some really bizarre twist of lighting and defective filter pointed at just the right angle to the sun, you could see some flaring that would act like a strip ND filter. So, take the filter off, load some cheap C-41 film in your camera, point it at a clear sky or some other even toned subject, and take some snaps at a fixed EI. Process the film and look at the film. If it is the lens, you should see some weird exposure patterns. If it is the shutter, at some speed you will start to see a graduated film density. If it was the filter then you will see no change as you don't have the filter on. Hope this helps. Don dorysrus@mindspring.com -----Original Message----- From: lug-bounces+dorysrus=mindspring.com@leica-users.org [mailto:lug-bounces+dorysrus=mindspring.com@leica-users.org] On Behalf Of Saganich, Christopher/Medical Physics Sent: Wednesday, December 08, 2004 12:28 AM To: Leica Users Group Subject: [Leica] Problem summicron uniformity Hello I took my leica to the beach with my summicron ASPH 35 and Orange/red filter. The shots all have noticable nonuniformity side to side. Darker on the sides then in the center by about one stop. Example: http://www.apug.org/gallery/showphoto.php?photo=4185&password=&sort=1&ca t=500&page=1 I went back over other rolls and noticed the same thing even with my M2, but didn't notice this with other lenses. I made a few test shots with my Voghtlander 35/2.8 with same filter and then made an identical shot with the ASPH Summicron 35, then without the filter. Similar patterns were observed for both lenses but less so without the filter. The question is whar should I expect from these lenses in terms of exposure uiformity? Is there a mechanical Issue with the shutter? Do filters cause these issues? Thanks, chris ===================================================================== Please note that this e-mail and any files transmitted with it may be privileged, confidential, and protected from disclosure under applicable law. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any reading, dissemination, distribution, copying, or other use of this communication or any of its attachments is strictly prohibited. If you have received this communication in error, please notify the sender immediately by replying to this message and deleting this message, any attachments, and all copies and backups from your computer. _______________________________________________ Leica Users Group. See http://leica-users.org/mailman/listinfo/lug for more information _______________________________________________ Leica Users Group. See http://leica-users.org/mailman/listinfo/lug for more information