Canon Patents

New Canon 600mm f/4 Design Uses Spotting Scope Trick

This site contains affiliate links to products and services. We may receive a commission for purchases made through these links.

Just a month after the Canon R5 came out in 2020, Canon filed a patent application – published only this morning – That attempts to make a smaller 600mm f/4, without resorting to fresnel DO optics and avoiding catadioptric designs that use a central mirror that blocks some light and causes doughnut bokeh.

img 728x597 - New Canon 600mm f/4 Design Uses Spotting Scope Trick

The new design places two optical tubes atop each other, with a couple figure-four mirror arrangements that bump the light from the top, larger aperture tube eventually down to the lower tube that contains most of the focusing and aberration-correcting lens groups. The movement of the light between the two tubes takes up 575mm of the 600mm focal length, allowing for significant length savings.

This results in a two-tubes-squished-together look seen commonly among spotting scopes.

Based on the back-focus being listed as 80mm, the length of this lens appears to be about 24 (~9.5 inches) centimeters long, only about an inch and a half longer than the RF 70-200 f/2.8 L lens when shot at 200mm. The objective lens element at the end, though, would have to be the same diameter as current 600mm f/4 lenses, making it quite a stubby design.

The center of gravity would be about the same distance from the camera as where one puts a hand under a 70-200 f/2.8 lens, giving the lens quite a lot more maneuverability.

Canon plainly decided to explore all strategies when looking to improve on its supertelephoto line-up when moving to the R mount. In the meantime, it repurposed its recent EF 600mm f/4 and 400mm f/2.8   Mark III designs by slapping a permanent R mount adapter on them.

It simultaneously designed and launched a brace of small-aperture 600mm and 800mm  f/11 fresnel DO lens to many positive reviews. The length of those lenses was abbreviated both by the fresnel element, and also with a collapsing optical tube that needs to be extended prior to use.

Very recently, other patents using the more traditional catadioptric “mirror lens” designs appeared from roughly the same time period.

The fact that the DO design effort required the addition of a telescoping tube to save length may indicate that Canon may have given up on the much-hoped-for 600mm f/4 DO lens that appeared briefly at a trade show as a prototype model seven years ago (pictured at top). Since that time, Canon embarked on a notably diverse research effort primarily to reduce size and weight of supertelephoto lenses, with the image quality remaining about equal to the excellent results first achieved with its EF Mark II supertelephoto lenses.

Canon’s recent announcement of variations on the RF 400mm f/2.8 and RF 600mm f/4 designs – adapting them into an 800mm and 1200mm offering through the uses of teleconverting lens groups – disappointed some, as many RF supertelephoto shooters were hoping for more design innovation than adapters and teleconverters on the older EF lense designs. The lenses’ reception didn’t get a boost from the announced pricing, with a roughly 30 percent boost in versus with the corresponding base lense.

The strategy of re-using older designs – especially ones considered close to optical optimums – could have proved popular if the efficiencies created resulted in more people being able to purchase them.

In the meantime, Nikon’s Z mount – long criticized for sporting a mostly amateur lens lineup – two days ago started delivering its 400mm f/2.8 lens that comes with an internal, switchable teleconverter, rendering the lens also a 560mm f/5.6. To top it off, it started seeding some pre-production models of its svelte 800mm f/6.3 fresnel-based design lens last week. That lens is rumored to cost about a third the price of the announced upcoming 800mm RF lens. That difference in price between Canon’s new 800mm lens and Nikon’s is about the price of a copy of Nikon’s new flagship Z9 camera.

Chaitanya

EOS 5D Mark IV
Jun 27, 2013
1,559
744
36
Pune
Current Canon Super tele lenses are a big middle finger from Canon to RF users.
 
  • Like
Reactions: 1 users

neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,904
6,181
Current Canon Super tele lenses are a big middle finger from Canon to RF users.
While I agree (and thus am not planning to upgrade my EF 600/4 II), I also believe they have other, higher priority design priorities than updating the supertele lenses with truly new designs.
 
  • Like
Reactions: 1 user

mxwphoto

R6 and be there
Jun 20, 2013
40
57
While I agree (and thus am not planning to upgrade my EF 600/4 II), I also believe they have other, higher priority design priorities than updating the supertele lenses with truly new designs.
Fine to have higher priorities, but when the additional teleconverter premium on the 800 and 1200 amounts to $4-6k, it is hard to see it as anything but that slap in the face. It is a rare disappointment in Canon's otherwise stellar RF lens lineup.
 
  • Like
Reactions: 5 users

Blue Zurich

SL,UT
Jan 22, 2022
160
236
Bring on those higher priorities (and let's see if they match with CR members wish lists)
 
  • Like
Reactions: 1 users

AccipiterQ

EOS 90D
Sep 11, 2014
193
285
I think the recently introduced lenses were clearly stop-gaps, right? It's like the R and the RP back a few years. I'm curious what the other priorities are though....R7 maybe?
 
  • Haha
Reactions: 1 user

melgross

EOS R
Nov 2, 2016
807
589
Bring on those higher priorities (and let's see if they match with CR members wish lists)
It doesn’t matter what our wish lists are. What matters is what the majority buying public buys. Unfortunately for us, that rarely matches our desires.
 
  • Like
Reactions: 4 users

Fischer

EOS RP
Mar 17, 2020
347
247
Next time there's a big white announcement that's not about the RF 300mm L IS I'll probably faint. o_O
 

robinlee

EOS M50
Mar 2, 2014
41
23
I really hope Canon announces something that rival Nikon's 500mm and 800mm PF designs. With current ISO performance there's no need for f4 lenses.
 
  • Like
Reactions: 4 users

mbike999

EOS M50
Jan 18, 2018
42
86
Bay Area
I don't need fancy design, don't really care about the length either. Just want an updated 500/4 and 300/2.8 with the modern 400/2.8, 600/4 EF/RF weight reduction treatment, focus motors, etc.
 
  • Like
Reactions: 1 users

entoman

wildlife photography
May 8, 2015
884
1,010
UK
I really hope Canon announces something that rival Nikon's 500mm and 800mm PF designs.
I think there will be plenty of serious wildlife photographers, and probably a bucketload of sports photographers, who are seriously considering switching to Nikon. We can only hope that Canon can quickly respond to the 500mm and 800mm PF designs, with lenses that are equally light and compact, equally good optically AND sell at a competitive, sane price.
 
  • Like
Reactions: 1 users

entoman

wildlife photography
May 8, 2015
884
1,010
UK
With current ISO performance there's no need for f4 lenses.
It's not all about light-gathering ability and fast shutter speeds. One of the major reasons why F4 super-teles are so popular with sports and wildlife photographers is the greatly reduced depth of field, which causes the subject to "pop" out from the background.

But F5.6 or F6.7 lenses would be a step in the right direction, forming a sensible and relatively affordable compromise between the 600mm F4 and the 600mm F11. The gap between these lenses is huge, and needs very much to be bridged.
 
  • Like
Reactions: 2 users

neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,904
6,181
But F5.6 or F6.7 lenses would be a step in the right direction, forming a sensible and relatively affordable compromise between the 600mm F4 and the 600mm F11. The gap between these lenses is huge, and needs very much to be bridged.
I suspect many people fill that gap with the RF 100-500L without or with the 1.4x TC.
 
  • Like
Reactions: 4 users

neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,904
6,181
Fine to have higher priorities, but when the additional teleconverter premium on the 800 and 1200 amounts to $4-6k, it is hard to see it as anything but that slap in the face. It is a rare disappointment in Canon's otherwise stellar RF lens lineup.
My point is that there was not much intensive design work needed to bolt on an RF adapter or a 2x TC with it. The new lenses are ‘halo’ products, and if you feel like they’re a slap in your face they probably weren’t for you anyway.

To me, the RF 400/600/800/1200 supertele lenses seem like Canon going after the low-hanging fruit from a design standpoint. The EF 400 and 600 were recently redesigned with many changes from the MkII. The 300 and 500 didn’t get that overhaul, so perhaps Canon will design them from the ground up, maybe with a built-in 1.4x or something else novel. But that’s more work, meaning more time, and Canon would rather develop products with a wider market first.
 
  • Like
Reactions: 1 user

Dragon

EF 800L
May 29, 2019
628
639
This looks like a neat alternative to mirror lenses. A bit of an odd shape, but, in the end, about the same size and weight as a mirror lens without the doughnuts or loss of t stop relative to f stop. The mirrors need to be accurately placed, but flat mirrors are cheap compared to lenses or even spherical mirrors. The drawing suggests the larger tube on the top, but it could equally well be on the bottom and that would be better for subject visibility and flash. The text of the patent also allows for the use of a DO element which would make the lens even smaller.
 
Last edited:
  • Like
Reactions: 1 user

Blue Zurich

SL,UT
Jan 22, 2022
160
236
It doesn’t matter what our wish lists are. What matters is what the majority buying public buys. Unfortunately for us, that rarely matches our desires.Tongue in cheek Mel, Tongue in cheek.
Tongue in cheek Mel, Tongue in cheek. My sentiment is exactly the same as your response, I just am always smirking at the general forum selfish perspective on the launches and announcements.
 

AlanF

Stay at home
CR Pro
Aug 16, 2012
9,581
14,294
It's not all about light-gathering ability and fast shutter speeds. One of the major reasons why F4 super-teles are so popular with sports and wildlife photographers is the greatly reduced depth of field, which causes the subject to "pop" out from the background.

But F5.6 or F6.7 lenses would be a step in the right direction, forming a sensible and relatively affordable compromise between the 600mm F4 and the 600mm F11. The gap between these lenses is huge, and needs very much to be bridged.
Agreed about the dof, and also with a high resolution sensor like the R5's, you will get better IQ with the lower diffraction from the f/4 and significantly lower iso required. What surprised me was that my RF 100-500mm at f/7.1 on the R5 gave virtually indistinguishable IQ from my Nikon 500mm f/5.6 PF on a D850 or D500. Accordingly, I wouldn't be interested in a RF 500 f/5.6 as any small IQ advantages would, for me, be much less important than the versatility of a close focussing zoom. But, the extra stop of a 500/4 might swing it for me for more specialised use.
 
Last edited:
  • Like
  • Love
Reactions: 2 users

Blue Zurich

SL,UT
Jan 22, 2022
160
236
The vast majority of the public buys 800/5.6 and 1200/F8's?
I truly missed with context on that, sorry. I was trying to say that a majority here want/ask/demand things Canon rarely produces and does launch other lenses which sell very well but may not be what this small niche desire. Then there's the 50 1.4 pleas which skew my entire joke premise.

Moving on....
 
  • Like
Reactions: 2 users