Canon LTM Some lens patents found (1.5/35 and 1.8/85)

Canon M39 M39 screw mount bodies/lenses
Sonnar2

Sonnar2

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Probably you heard about Rudolph, Bertele, Mandler, Tronnier and their fantastic lens designers work? But what's about Jiro Mukai of Canon?


http://www.google.com/patents?vid=USPAT3066575&id=jMBjAAAAEBAJ&pg=PP1&dq=jiro-mukai

The famous 1.8/85. Normally things develop from simple to complicate but not in this case. Mukai took the 2/100, combined the 4th and 5th element to one and got a very compact 85's of elite quality. See the sleek aberration curves.

http://www.google.com/patents?vid=USPAT2926564&id=SydtAAAAEBAJ&dq=jiro-mukai&jtp=1#PPP1,M1

The 1.5/35mm... compare the curves of spherical aberration and astigmatism with the above... Mukai claims a highspeed wideangle lens of f/1.4 but this was a bit overstretched. I remember a f/1.4 prototype sold last year in a Japan auction for a decent price, discussed here as well.

But still better corrected than the 2.8/28, see here:
http://www.google.com/patents?vid=USPAT2779239&id=Ue1NAAAAEBAJ&pg=PA1956&dq=2779239#PPA1956,M1

have fun reading,
-Frank-
 
You need the exact design: radii, adjustments of elements, refractive index of glass used etc. For example, a lens adjustment very similar to the (jn)famous 0.95/50 was patented as early as 1934 by H.W.Lee (US patent 2012822, Fig.3) - so after all Mr. Hiroshi Ito's 0.95 was a common approach incorporating just som new glass types.

cheers, Frank
 
Agreed, this is fascinating stuff. The resources of the web never fail to astonish me. The design team at Canon must have been top notch from the beginning, based on the lenses performance and the patents granted to several individuals.

I don't think anyone quibbles about the 50/1.8 or 1.4, and most agree on the 35/2. Even with the debates on the 50/0.95 and 1.2, there is a clear message from many that these are good tools to accomplish a difficult task. Most of us don't remember when ASA 100 was a fast color film, and 16 or 25 was the fine grain choice. A few here will remember Tri-X as almost miraculous when it was first released. The high speed lenses were much more of a necessity back then, or many images would have been impossible to capture. Coupled with the time consuming math tools available, compared to our computer age, these guys were skilled and inventive, indeed.

Thanks Frank, for your search and discoveries...

Harry
 
I just found the patent on the great little 3.5/100mm as well. Hiroshi Ito was the designer as well. The claim is on "the smallest telephoto lens with a speed of f/3.5 well corrected for sperical aberration, astigmatism and distortion" (DE1922027). We do well know this is still a great lens to use...

He made also the big glass 1.5/85mm, "particulary good corrected for coma".

So as far as lenses are concerned, 1951 was the first great year for Canon...

Happy New Year!
-Frank-
 
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Hi John,
not every patent was realized the same way in series. According to R. Hooper (LHSA article: The other 35mm) and sources on the web (I believe D.Stella) the 2/35 was derivated from the 1.8/35 design-wise and looks like this:

http://www.taunusreiter.de/cameras/35mm_3.pdf

So the 2/35 is more kind of an "evolution" than an invention. But what I'm looking for is the patent on the great standard lens 1.4/50mm. Most trustable sources say it was launched 1959, so it's probably designed by Mukai. I wonder if this man hadn't claimed a patent for getting the first well-corrected 1.4/50mm lens made of just 6 elements...

canon1450.jpg


cheers Frank
 
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