OlivierAOP
medium format
Yes the dates don't match. I find it strange that there doesn't appear to be a patent for the Canon f/0.95. The Delft one references the Canon f/1.2 so you'd think that if the f/0.95 existed it would be referenced as well? And then the Canon goes on to be produced in large numbers for 20 years (including the TV version).
There is a good chance that I'm on a false lead. If I had access to an optical lab or lens designer I could verify. Fascinating stuff really.
There is a good chance that I'm on a false lead. If I had access to an optical lab or lens designer I could verify. Fascinating stuff really.
Mackinaw
Think Different
You should pick up a copy of Arthur Cox's book on optics (mine is 1974). He writes about several of Canons high-speed rangefinder optics in his section on symmetrical lenses.
Jim B.
View Range
Well-known
Olivier, there could be a Japanese patent for the 0.95. It won't appear in the US patent listing and may not have been known to Old Delft / US Patent reviewers.
OlivierAOP
medium format
Thanks for steering me in the right direction. The Oude Delft patent was indeed a false lead. I was able to find the Japanese patent! It's a bit of a miracle as those old patents are not indexed by keyword/author/company and are in Japanese only.
Here is the URL. You can also find it by searching 1960-043650 on the patent site. I can't read Japanese but I was able to match the characters for Canon and Jiro Mukai in the document.
The prescription appears to be a better match to my experiments. Hard to be sure without proper equipment but I hope that's it.
Here is the URL. You can also find it by searching 1960-043650 on the patent site. I can't read Japanese but I was able to match the characters for Canon and Jiro Mukai in the document.
The prescription appears to be a better match to my experiments. Hard to be sure without proper equipment but I hope that's it.
OlivierAOP
medium format
Quick update. A friendly optician made me a replacement element at a reasonable cost. Not the exact glass/radii as per patent but close enough (at least according to ray-tracing data).
I've only tested it briefly (on crop sensor, my a7 died
). Seems comparable to the proper 0.95 lens? At any rate it's a though lens to use at 0.95: soft and low contrast but nice oof areas. I'll likely get better in post-processing!
I've only tested it briefly (on crop sensor, my a7 died
). Seems comparable to the proper 0.95 lens? At any rate it's a though lens to use at 0.95: soft and low contrast but nice oof areas. I'll likely get better in post-processing!
raid
Dad Photographer
Congrats! Your long battle with this lens may be over.
Jhausler
Established
Would love to see some images of the replacement parts, and images taken with it. Congrats!
OlivierAOP
medium format
Here are some thumbnails of the ghetto 0.95. I'm using an helicoid coupled via a ring made by RAF camera. Focuses much closer than the 1m of the original but I would like to cover the aperture linkage. I'll post pictures eventually when I repair/replace the full frame camera.
