Does anyone know where on the web I could find a schematic of the Summicron/Rokkor 40mm? Is it like the Summicron 50 or 35?

-- J. Galloway (jgall30125@aol.com), October 03, 2000

Answers

Here is a website that has a lot of info on the CL / CLE, including the lenses. The author makes good comments about the relative comparison between the 40mm lenses and "true" Leica lenses... basically, they are very well matched... comments about 30 X 40 inch prints made with the 40. I think that you are requesting a cut-a-way view, showing the elements... sorry, but I could not find one on the net with all of my bookmarked leica sites. Hopefully, this site will at least give you confidence that the lenses are great.

http://www.cameraquest.com/leicacl.htm

-- Al Smith (smith58@msn.com), October 03, 2000.

Found a couple of other sites... still no cut-a-way view, but one site has Chart with elements and groups.

Elements / groups:

http://www.cosmonet.org/camera/leiccl_e.htm

Lens Compatibility:

http://www.multimania.com/cesarigd/photoe2cleo.htm

-- Al Smith (smith58@msn.com), October 03, 2000.

A point to note here is that schematics published over the years, in several books, such as The Leica Compendium, or the Leica Manual, or Photgraphic Optics by Cox, show that the 50mm Summicron doesn't even resemble itself too closely in its various versions. For this reason it might be difficult to divine much about the 40mm, or how it compares to other Summicrons. I should imagine it probably is a gaussian design, with a pair of cemented groups, each having a deeply concave surface facing each other from opposite sides of the diaphragm; possibly a thin lens airspaced and interposed between one or both of those concave surfaces, and the diaphragm; and single element positive components for the front and rear elements. This is the basic setup of the 35mm Summicron of the time period. But, then again, the 90mm Summicron doesn't adhere to this type of formula, and this too makes me question how much we can figure out by examining the schematic. Why not ask some users to comment on the performance of the 40? I think it's supposed to be good, but I've not used one.

Regards,

-- Bob Fleischman (RFXMAIL@juno.com), November 23, 2000.

I looked at the website Al Smith cited (I should have done this in the first place). The lens has 6 elements in 4 groups. If you have access to the Leica M Compendium, take a look at the 35mm Summicron on page 51. Now, take away the thin lens just to the right of the diaphragm, and the remaining components, I feel pretty sure, would bear a close resemblence to the 40mm Summicron.

That's the best I can do. Hope it helps.

-- Bob Fleischman (RFXMAIL@juno.com), November 24, 2000.

Late response: you'll find the optical construction schematic near the bottom of this webpage: http://www.kscamera.c o.kr/leica/m/m35.htm

-- Hoyin Lee (leehoyin@hutchcity.com), September 09, 2001.

Thanks for that good site.

-- John Galloway (jgall30125@aol.com), September 10, 2001.