Archived posting to the Leica Users Group, 1998/10/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Once in a while when I don't feel the creative inspiration to go out and photograph seriously, I also like to run lens tests (and in the process the bodies get tested as well). I have the 35/2 ASPH as well as my previous Summicron (1974 6-element), and a 1964 2.8 Summaron and 1953 3.5 Summaron (in LTM). The only observable difference I've found between the '74 and the ASPH is an increase in contrast and decrease in optical vignetting at full aperture. By 2.8 no non-photographer I've asked can tell them apart and by f4 I haven't found a photographer who can see a difference. By f5.6-f8 even the 2.8 Summaron comes round and gives the later lenses a good show. The 3.5 Summaron is a good little...in fact, quite tiny...lens but it can't quite keep up with the others. As to checking the rfdr, I simply mount the camera with a 90 or 135mm lens on a tripod, remove the baseplate and rear flap, hold open the shutter on B with a locking cable release, and tape an old focussing screen from a reflex camera (matte, flat side facing the front of the camera) which I've trimmed to fit in the film plane and sit flush against the film rails. I then view this with an 8x loupe and check focus of objects at various distances as against the rfdr. Regards, Nigel On Sat, 10 Oct 1998 23:00:09 +0200 Nathan Wajsman <nathan.wajsman@euronet.be> writes: >My M6 has recently come back from a trip to Solms for rangefinder >adjustment. To make sure that the problem had indeed been solved, I >ran >some tests last week. What I did was the following: > >1) Mounted the camera on a sturdy tripod. >2) Focused on an object about 0.9 meters away until the image looked >sharp in the viewfinder. >3) With my 35mm Summicron (2nd version), I exposed at f2, f2.8, f4 and >f5.6. >4) Repeated the exposures without moving the camera but with the lens >focused at 0.8 m. >5) Repeated again, this time with lens focused at 1.0 m. > >I then proceeded to do the same test with my 1.4/75mm Summilux >(apertures f1.4, f2, f2.8 and f4) and the 2.8/90mm Elmarit-M (f2.8, >f4, >f5.6). Since the minimum focusing distance of the latter lens is 1m, I >had to move the camera back a bit, so that the subject to film plane >distance was about 1.1m. > >I did the tests using Kodak's E200 film (I know I should have used >Fuji >Velvia but did not have around the house). I looked at the slides on a >light table with a 10x loupe. > >Some conclusions: first, it appears that my rangefinder now functions >correctly, as the image that looked right in the viewfinder was also >the >best compared to the other two focus settings. Second, with the 35mm >Summicron there was a distinct difference in image quality going from >f2 >to f2.8. At f2 the image was a bit soft, even in the centre, and >vignetting was obvious (although not uniform in all four corners). >This >has me thinking about upgrading to the 2.0/35mm Summicron ASPH. >According to Erwin Puts, there is a significant difference between the >newest lenses and the older ones especially at full aperture and close >distance. I would like to hear from someone who has upgraded from the >old to the new Summicron--did you experience a visible quality >(sharpness) improvement? Third, with the 75mm and 90mm lenses, the >improvement when stopping down from full aperture was much less >pronounced and hardly visible with the 90mm Elmarit-M (just bought in >Bonn in September). In general, based on this limited test, I have >concluded that the 90mm Elmarit-M is sharper than the 75mm >Summilux--but >on the other hand the Summilux gives an incredible image quality >considering the f1.4 maximum aperture. > >Nathan > >-- >Nathan Wajsman >Overijse, Belgium > >Photography page: http://members.tripod.com/~belgiangator/index.html >Motorcycle page: >http://www.geocities.com/motorcity/downs/1704/index.html > > > ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com or call Juno at (800) 654-JUNO [654-5866]