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

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Jan 19, 2014
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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.
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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...

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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.
 
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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.
 
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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.
 
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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.
 
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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.
 
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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.
 
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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.
 
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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.
 
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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....
 
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