Canon Patents

Patent: Canon RF 50mm f/1.4 USM and other primes

Canon Rumors
Posted onNov 5, 2020 at 8:50 AM
Updated onUpdated on Nov 6, 2020 at 8:16 AM

A new Canon Japan patent shows the optical formulas for various RF 50mm f/1.4 designs as well as an RF 35mm f/1.4. This patent deals with increasing focusing speed when using lens designs with large diameter elements.

I don’t think any of these optical formulas will become products, so the dream of a new 50mm f/1.4 from Canon probably won’t be coming true any time soon.

RF 50mm f/1.4 RF 50mm f/1.4 RF 50mm f/1.8
Focal length 51.50mm 48.47mm 48.49mm
F value 1.45 1.45 1.45
Half angle of view 22.79° 24.05° 24.04°
Image height 21.64mm 21.64mm 21.64mm
Lens length 95.19mm 108.84mm 91.98mm
Backfocus 11.49mm 11.39mm 11.48mm
RF 50mm f/1.4 RF 35mm f/1.4
Focal length 48.49mm 33.99mm
F value 1.45 1.45
Half angle of view 24.04° 32.48°
Image height 21.64mm 21.64mm
Lens length 116.56mm 131.16mm
Backfocus 13.23mm 12.05mm
Canon Rumors
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S

SwissFrank

from EOS 1N to R
Dec 9, 2018
467
212
These designs somehow don't look like real designs, but rather examples of trying to have lots of heavy elements on purpose... I've never seen so many cemented doublets
 
melgross

melgross

EOS RP
Nov 2, 2016
664
441
Remember the days when a 50 f1.8-2.0 was a basic Gaussian 6 element design, and the bigger, more expensive f1.4 had 1 more element? The f1.4 also had higher quality. My 50 f1.4 FD was considered to be a superb lens. I suppose today it would fail every test. All of my FD lenses, the pro models, are considered as tiny today.

though my 100mm f2.8 is still one of the sharpest lenses I’ve ever had.
 
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Antono Refa

Antono Refa

EOS R
Mar 26, 2014
1,182
344
melgross said:
My 50 f1.4 FD was considered to be a superb lens. I suppose today it would fail every test.
Click to expand...
The standards have changed in the past few decades. Technically, sensors have more details than most films, and the standard of living has raised, and people can and do print larger.
 
melgross

melgross

EOS RP
Nov 2, 2016
664
441
Antono Refa said:
The standards have changed in the past few decades. Technically, sensors have more details than most films, and the standard of living has raised, and people can and do print larger.
Click to expand...
Yes, that was the point. My company used to process Kodachrome. We had our own pro process. I used to write for Kodak’s Lab Notes. I’m about as familiar with this as anyone. Kodachrome, according to Kodak, was equivalent to about 14-18MP. So that gives an idea. But that 100 f2.8 is still a very sharp lens. I’ve got an adapter for FD lenses on the EOS mount. Unfortunately, you can’t focus to infinity with it, but otherwise, you can use those lenses. On my 5D mk IV, it’s still pretty damn sharp. Surprising, but true.
 
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Sporgon

Sporgon

5% of gear used 95% of the time
CR Pro
Nov 11, 2012
4,020
532
Yorkshire, England
www.buildingpanoramics.com
melgross said:
Kodachrome, according to Kodak, was equivalent to about 14-18MP.
Click to expand...
Which Kodachrome ? The only one I have found to come close to 14 mp in resolution and 18mp in colour definition was Kodachrome 25. (35 mil of course).

But I've also found that fine grain 35mm film is as brutal on lenses and technique as a 5DS when you start scanning and outputting to the same kind of sizes we routinely do today.
 
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melgross

melgross

EOS RP
Nov 2, 2016
664
441
Sporgon said:
Which Kodachrome ? The only one I have found to come close to 14 mp in resolution and 18mp in colour definition was Kodachrome 25. (35 mil of course).

But I've also found that fine grain 35mm film is as brutal on lenses and technique as a 5DS when you start scanning and outputting to the same kind of sizes we routinely do today.
Click to expand...
K-25.

nah, film is easy, by today’s standards. And by the way, lens manufacturers used to lie all the time about flat field (Leica, I’m looking at you!). Film in film gates where the back plate doesn’t clamp down on the film, isn’t flat. Think about everything that film is and what the requirements for mechanical operation is, and you’ll understand why. It’s a major reason why film lenses can be fairly sharp in the center, and so bad everywhere else, for digital. That’s for lower rez digital. We began, in my lab, to see that for 6MP.
 
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D

dsut4392

EOS M6 Mark II
Jul 31, 2014
80
34
Ziz said:
a Compact 50 f1.4 usm, weather-sealed ....please!!!
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I don't even care about USM as long as AF is accurate, just make it compact and give it good bokeh. an RF version of the Sigma 50/1.4 EX would be perfect.
 
D

Del Paso

M3 Singlestroke
Aug 9, 2018
968
996
melgross said:
K-25.

nah, film is easy, by today’s standards. And by the way, lens manufacturers used to lie all the time about flat field (Leica, I’m looking at you!). Film in film gates where the back plate doesn’t clamp down on the film, isn’t flat. Think about everything that film is and what the requirements for mechanical operation is, and you’ll understand why. It’s a major reason why film lenses can be fairly sharp in the center, and so bad everywhere else, for digital. That’s for lower rez digital. We began, in my lab, to see that for 6MP.
Click to expand...
That's exactly what I noticed with an old Leica M Summicron 35 f2 , extremely good on Kodachrome, but marshmallow soft corners on Leica digital bodies under f8. Same applies to the Leica R 28mm f2,8.
Yet, the 50 M, 75 M, 90 M, 135 M and all the other Leica R APO vintage lenses are still tack sharp, even in the extreme corners.
Even most of my Olympus lenses were unusable for digital... and got sold:cry:
 
justaCanonuser

justaCanonuser

Grab your camera, go out and shoot!
Feb 12, 2014
710
513
Frankfurt, Germany
Finally, a new 50mm f 1.4! High time, the EF version is really old design, very soft wide open ... I waited many years for a new EF version in vain, now, with the new mount, it doesn't come as a surprise.
 
melgross

melgross

EOS RP
Nov 2, 2016
664
441
Del Paso said:
That's exactly what I noticed with an old Leica M Summicron 35 f2 , extremely good on Kodachrome, but marshmallow soft corners on Leica digital bodies under f8. Same applies to the Leica R 28mm f2,8.
Yet, the 50 M, 75 M, 90 M, 135 M and all the other Leica R APO vintage lenses are still tack sharp, even in the extreme corners.
Even most of my Olympus lenses were unusable for digital... and got sold:cry:
Click to expand...
What’s interesting is how manufacturers handled backfocus. Back then, with manual, analog cameras, there was no backfocus adjustments. A manufacturer decided where to put that main focus at. Sometimes, it was closer to the front, sometimes to the rear. Some lenses were sharper with thinner b/w film, and some with thicker color film. Some were even aimed at thick Kodachrome.

by the way, apochromatic lenses aren’t necessarily sharper, nor do they always have flat field. It just means that three colors focus on the same plain, curved or flat. Stopping down a couple of stops, as always, results in better performance across the frame.
 
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