Canon had first RF with TTL metering patented in 1958

Sonnar2

Sonnar2

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Imagine:

pat 2937582 filed Feb 1958....

honors to CANON and Takeshi Goshima

see http://www.google.com/patents?vid=U...J&printsec=abstract&zoom=4&dq=2937582#PPP3,M1

The System looks very much like the Leica M5 metering system many years later...

TTL_02.jpg


Looks like: a Canon VI-L with TTL metering, hu?
What a pity it was never made to serial production. Two years before ASAHI PENTAX
showed the SPOT-MATIC prototype at the Photokina in Cologne... In his patent 3091161 Pentax engineer Saburo Matsumoto (filed May 1961), inventor of the SLR TTL metering took reference to Goshima's patent.

TTL_01.jpg


Happy Christmas to All of You...
Frank
http://www.taunusreiter.de/cameras/canon_Main.html
 
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Still, rather elegant. It would be interesting to have seen it in action. Makes me wonder, as well, what was going on under the hood of the Kiev 4TTL prototype...

William
 
wlewisiii said:
Still, rather elegant. It would be interesting to have seen it in action. Makes me wonder, as well, what was going on under the hood of the Kiev 4TTL prototype...

William
Click to expand...

That would be cool indeed! Lets add a cloth shutter too and parallax corrected frames for 35, 50, 85. and have the VF show about a 28 FOV, with at least a .75x magnification. Don't forget the Hot shoe that's cuts the juice after the shutter is tripped. And for $100.00 USD plus S/H. "Kiev 4-TTL

Hay, I can keep dreaming can't I ??
 
erikhaugsby said:
Does anybody know why Canon didn't do anything more with this? A lack of R&D capital, prehaps?
Click to expand...

In 1958 the meter cell would have been selenium, and a selenium cell small enough to fit behind the lens (and having to read at working aperture) would have been very limited in sensitivity.

How do I know that? Because somebody else -- Feinwerk-teknik of Lahr, Germany -- actually tried it, in a 16mm subminiature camera called the MEC 16SB. This little camera used a hinged selenium meter cell that read at working aperture from behind its 22mm f/2 Rodenstock Heligon lens. It did work, but limited sensitivity was a problem.

Incidentally, depending on whether you believe this or this online source, the MEC 16SB was introduced either in 1957 or 1960; if the 1957 date is correct, I wonder how Canon was able to get a patent, since their system was so similar.
 
Based on the date of the patent, I'd say they had already decided that the SLR was the future. Hence the simpler to produce metering on the 7 series...

Arbib: the Kiev 5 has a finder very much like what you suggest. 35 fov overall with parallax corrected brightlines for 50 & 85. The RF patch, as always on a Contax derivative, is good enough to cover the 135. Big, clear, bright... it's a marvellous finder. Had the rest of the camera met that standard, the 5 would probably have been a landmark camera. Sigh. I'm going to end up with another one someday, I just know it...

William
 
You don't see an electric curcuit or a battery on the drawings, which was the weak part of the claim. So it couldn't be anything else than a Selenium cell - which simply is to big. So the claimed solution wasn't working with 1958' photo cells, period. As far as I know Pentax was among the firsts who had a CDS cell meter attached to the prism in series - 1961 - although it took them 4 years to develop their Spotmatic prototype into series. The first Pentax TTL-patent also wasn't very detailled. All you can see is the same kind of "moving arm" with a small photo cell. After all, Canon was two years ahead at that time.

Why they didn't developed it further? I don't know. Maybe there were too late with cds-cells (Canon FX as late as 1964, /s 1965), and then the future was SLR. And for sure the metering as realized in the model 7 was more fool-proof than any spot-metering system with a moving arm manually triggered by the photograph.

There was an article in German PhotoDeal quoting a Voigtlaender prototype SLR with TTL-metering and cds-cell as early as 1959 (design Swarofsky) but I have my doubts about the date. The patent was filed not before 1962. Maybe just another German Zeiss-Ikon-pushed-down-Voigtlaender legend.

On the sketch the galvanometer isn't coupled to shutter dial, true. After all, the first camera with a cross-coupled meter (both to aperture and shutter speed) was the Contarex 1959 (bull-eye). But there is another Goshima-Canon patent with shutter-speed coupled meter (2952194), just the way they realized it with the Canon 7. So combining these inventions was no quetsion.

Anyway, a pity Canon didn't make good use of their 2 years advantage towards Pentax. They slept. If you compare the later development of SLRs of both makers in the 60's, it was Pentax who made the run and Canon wasn't particular successfull with SLRs until launching the FT/ F-1 models, probably this having a big part on the severe financial difficulties Canon faced in the end of that decade.

cheers, Frank
 
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