Canon LTM Canon 50/1.5 vs. 50/1.4 type 1 vs. 50/1.4 type 2

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Mackinaw

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Canon lens aficionados and collectors may find this interesting. Attached are lens schematics for the 50/f1.5, 50/1.4 type 1 and 50/1.4 type 2. For the Sonnar fans among us, the 50/1.4 type 1 is a very interesting lens as it seems to be derived from the 50/1.5.

Jim Bielecki
 
IIRC, Joe, your's is a type 1. With the 50/1.5 prices, I should have held out for more ;)
 
I don't think that any of the Canon 50/1.4 lenses had the Sonnar design that the 50/1.5 had. Certainly Canon's site shows both types 1 and 2 as having 6 elements in 4 groups -- a double Gauss (Planar) design. Same for Dante Stella's site.

Now, Nikon's RF 50/1.4 is a Sonnar design, as was the preceeding 50/1.5.
 
Take alook at the first two schematics in my original post. The first is of the 50/1.5 and shows the classic Sonnar formula. The second schematic, of the 50/1.4 type 1, to my eyes, sure looks to be Sonnar-based (the first and second lens groups, while not identical, show a certain family resemblence). Whatever, Canon must not have been satisfied with the results since the 50/1.4 type 1 was only in production from November 1957 to March, 1958.

Jim Bielecki
 
Optical formulas only need slight variations to be VERY different. When I look at your three posted examples I see three very different lens designs.
 
Canon brought out a lot of new glass with higher index of refraction to reduce the number of elements used in their lenses. The Nikkor and Zunow F1.1 lenses were 9 element designs. The Canon 50mm F1.2 and F0.95 were 7 element designs using the newer glass. If Canon brought out an 8 element Sonnar variation I'll bet it was to use up older style glass. That rear element is there to reduce the required power of the rear 3-element cemented module of a traditional Sonnar. Leica used the same style variation in going to the 7-element variation of the typical 1-2-2-1 Xenon. The rear element was split into two elements, each of lesser power. Kind of defeats the design-goal of the Sonnar to minimize the number of air/glass interfaces.
 
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But the second drawing is 8 elements in 4 groups. Canon's own website says both types of the 50/1.4 were 6 elements in 4 groups. Not to mention everything else I've seen. Where do your drawings come from?

All the discussion I've read says that Canon really mastered the double-Gauss design to make the 50/1.8 and 50/1.4. The 50/1.4 is one of the first double-Guass 50/1.4 lenses, nobody else had managed to correct one well enough before then. Probably took some then-exotic glass. Of course, many SLR 50/1.4's in the years to come were double-Gauss.
 
Most 50mm F1.5 and faster lenses are 7 elements; the Canon 50mm F1.4 is one of the few 6-element super-speed lenses around. It performs quite well.

The "Modified Sonnar" looks like a typical 7 element in three groups with an additional rear element. The power of the 3-element element rear group would be reduced with the addition of the 8th element. Canon's website indicates Type 1 and Type 2 lenses are 6 element 4 group (classic 1-2-2-1 Xenon) design. I know my 50mm F1.4 is that design, I have removed the rear group for cleaning.
 
Hi Jim, where do have theses diagrams from??! Highly interesting!! But I would question if the 1.4/50mm first version is truly a Sonnar! (although Canon Camera Musuem isn't completely right in every aspect). To my knowledge the diiference between 1.4/50 Vs.1 and 2 is just barrell, like Brian states as well (broader focussing ring with dual - meter and feet - scale).
If there is more, then the pictures taken with these two types should differ more. In fact, it's not difficult to distinguish the typical "Sonnar" vs. "Planar" look!
Buit if diagram 2 isn't a Canon, I'm interested to know what it is!

cheers, Frank
http://www.taunusreiter.de/Cameras (<- has updated)
 
John and Brian, you are both dead right with your suggestion of CANON beeing the first bringing a f/1.4-50mm-lens of satisfiying quality of the Xenon- or Biotar-type (Double Gauss with 6 elements/ 4 groups) worldwide to production for 35mm (stand picture) film. Even if Schneider-Kreuznach and Zeiss invented this type in the middle 1920's (but just of smaller coverage/ angle of view for movie film, or 75mm focal length). Probably this could be managed only thanks newer glass!
Leitz in that era has a 7-lens-Xenon design (one single rear element added) but most people agree that the Canon of that vintage was the better lens!
See diagrams here (the text is in German currently):
www.taunusreiter.de/Cameras/Biotar.html

cheers, Frank
 
As mentioned in other unrelated posts (the 35/2.0 thread) the Canon schematics you see are scans from Randal Hooper's excellent and detailed Canon rangefinder article (actually a series of articles) that appeared in the "Viewfinder" back in the early 1990's. These articles are the best I've seen on Canon rangefinder lenses anywhere and are a "must-see" if you are a Canon rangefinder fan. Hooper includes production data, production dates, info and pictures on viewfinders, lens hoods, etc. with his information being more detailed and comprehensive than what I see in the Canon Museum. I have no idea where Hooper got his information but the amount of detail (especially the production data) lends me to believe that it came from somebody inside Canon.

Quibble all you want all you want about optical formulas, I still maintain that the 50/1.4 type 1 as depicted by Hooper, is a knock-off of the 50/1.5. It's totally conceivable to me that Canon lens engineers did their best to tweak the 50/1.5 formula before realizing it was an optical dead end and moving to a gauss formula we see in the 50/1.4 type 2.

But I'm also the first to admit I know very little about optical science and will leave it to you guys to argue the details. I'm going outside and take some pictures.

Jim Bielecki
 
Another argument can be made that CANON in 1956 brought a 1.2/50mm to production (fastest lens in the world then) which was a clear Gaussian design of 7-elements/ 5 groups. Therefore no need to come back 2 years later with an 8-element Sonnar design 1/2 stop slower, but even more expensive in manufacturing than the outdated 7-elements Sonnar type which was to replace. I'm sorry that the "viewfinder" Canon series of 1992 isn't generally available for crucial evaluation and comparison with other sources.

cheers, Frank
http://www.taunusreiter.de/Cameras
 
Until someone takes a type I lens apart, or has the manual for it with a block diagram, it will be hard to know for sure. I have found typo's in Neblette's book by comparing multiple books giving the block diagrams of lenses. I knew Neblette had interchanged the formula for the Nikkor 5.8cm F1.4 lens with the Summicron RF lens of 1971 as I have the old Nikon books giving the lens formulas. I know my Canon 50mm F1.4 is a Xenon because I took it apart.

It is certainly possible that Canon brought out the modified Sonnar for a short time period to use up older glass, but had to have an "F1.4" lens because Nikon offered one. The new glass was going into the F1.2 lens, and given its size there certainly could have been a shortage. These companies were very efficient. Nikon's first "rigid, non-collapsible" 5cm F2 S-Mount lens was nothing more than the collapsible lens with a metal tube over the lens barrel to keep it from collapsing! And the LTM lenses of the same period remained collapsible. As soon as the old parts were used up, out came a true non-collapsible barrel.
 
So Brian which version was the 1.4-50 you took apart?? Was "Cleaning and lubracating a Canon 1.4-50" yours? According to Canon Museum version 1 is with the smaller focussing scale (feet) whereas version 2 has meter as well as feet, so the lens mentioned there is a Ver.2.
From my observations most auctioned lenses of the 1.4-50 in the last years were "Ver.1". Of course I would favorize that one with "meter" scale if this would be the only difference.
Anyway, for optical formulas beeing so different, quite small a change in lens barrel, what do YOU think?

About the Nikkor-1.4-58, can you send me the diagram? How is it different from the SLR 1.4-50?

cheers, Frank
 
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