Re: [Leica] Canon lenses on Leicas

["Henning J. Wulff" <henningw@archiphoto.com>]

At 6:40 PM -0500 3/20/00, LRZeitlin@aol.com wrote:
>There has been recent postings on the quality of some older Canon lenses.
>Some Leicaholics find it hard to admit that Canon RF lenses function superbly
>on screw mount and M series Leicas and are available at about half the price
>of comparable used Leica lenses. All Canon RF lenses, except the 50mm F.95,
>were equipped with 39 mm screw mounts and rangefinder cams which coupled with
>Leica rangefinders. When fitted with screw to bayonet adapters, they all work
>on the M series cameras. The lenses were manufactured to the highest
>specifications and most were extremely sharp, even by today's standards.
>During my newspaper days, I bought a couple of these lenses and inherited a
>few more when my compatriots switched to SLRs.
>
>Here are my personal Canon lens favorites:
>25mm F3.5 - This is a unique Gauss-type lens similar to the Zeiss Hologon and
>uses a special optical glass plate to minimize falloff and distortion. It
>delivers crisp and sharp results to the edges of the negative. Use any
>adapter since you will have to get an accessory finder. One came with my lens
>but any superwide finder will do. It is hard to find but worth the search.
>
>35mm F2.8 - This older lens is similar to the Summaron and produces results
>identical to the Leitz optic. I use it on both screw mount Leicas and the CL.
>The full frame of the CL finder matches the lens picture area pretty well.
>Use a 35mm adapter. Canon also made a 35mm F2 and a 35mm F1.5 which I never
>tried. I have heard that they are both quite good though.
>
>50mm F1.4 - I bought this lens when I couldn't afford a Summilux. I've never
>compared side by side enlargements with the Leica lens but I have matched it
>with a seven element F2 Summicron, allegedly the highest resolution 50mm
>Leica lens ever offered. From F2 to F16 the results are almost identical with
>the Leica lens having the edge only on enlargements greater than 11x14. For
>half the price and the extra stop, this lens is a great buy for the Leica
>user.
>
>50mm F1.2 - I was given this saucer sized piece of glass by a colleague who
>had his Canon 7 body stolen. Most users (me included) have a love/hate
>relationship with the Canon 50mm 1.2. This mammoth sized optic has a screw
>mount but the lens is so wide that it is visible in the view finder of the
>camera. It is soft at full aperture, but sharpens up nicely at f4. It is not
>quite as good as the F2 Summicron but better than the 50mm Elmar. At F1.2 it
>gives a mysterious quality to the image, a sharp core with a soft halo. It
>takes very flattering low light portraits and makes an excellent natural
>light wedding lens since everyone looks beautiful. Available light photos,
>for which this lens was intended tend to be very contrasty and the full
>opening softness is suitable. It is a BIG hunk of glass to hang on your
>camera and it is impressive as hell mounted on an M3. The M2, M4, and .72
>viewfinder M6 don't have enough RF equivalent baseline to critically focus
>this lens at short distances (under 2 meters). The screwmount Leicas do,
>however.
>
>100mm F3.5 - This is my favorite short telephoto, bar none! It is razor sharp
>and beats every similar focal length Leitz optic I have tried. If you need a
>short telephoto, beg, buy, or steal this lens. I use it with both M series
>and the CL. Its picture area is fractionally smaller than the M finder field
>but matches that of the CL perfectly. It and the Leica 40mm make a great
>travel package for the CL. Use a 90mm adapter.
>
>135mm F3.5 - This is a solidly built telephoto that weighs almost a pound. It
>works fine with my M3s but is a bit too much focal length to focus accurately
>with later models. It is sharp to the edges and has little flare. Use a 35mm
>adapter on the M3.
>
>LarryZ

I've had some of the Canon lenses, and while generally good performers, 4
of 5 had had centering problems. All except a 50/1.8 were in near mint
condition when I bought them, and didn't appear to be abused in any way.

BTW, not all Canon thread mounts are compatible. A number of variations
were produced until about 1952. According to Peter Dechert ('Canon
Rangefinder Cameras 1933-168') Canon made some of the mounts with so much
play that they could be attached to both the J thread cameras and the LTM
cameras, in spite of the J pitch being 1.1mm (Leica - 0.977mm) and the J
throat diameter being nominally about 0.5mm less than Leica's. After 1952
apparently both Nippon Kogaku and Canon realized that the Leica's flange
pitch was 26 threads to the inch, and not 1.0mm exactly. This 1.0mm pitch
was used mainly in the late 40's.

Marc Small is the guy to ask about all the gory bits.

   *            Henning J. Wulff
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