Canon Gets 300mm Creative
- Thread starter Richard CR
- Start date
The EF 200-400mm is anything but light and easy to lug around. But then I have only rented a 600mm once for a specific event (Red Bull Diving Cup) a couple of years ago.
If I keep using the 200-400 for a period of time, I always get pleasantly surprised at how short, light and handy the EF 300mm f/2.8L feels when I pick it up. And it pairs beautifully with the 2x TC (contrary to most other lenses).
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My original point seems to have been missed. While the lens patent is for 295 mm or so, the optics of the lens are crammed into a length of 184 mm, with the exception of what appears to be the insertable filter. That is very compact. Those hunks of glass still need to be 70 mm or so from the image plane but that is what makes the insertable tele converter possible. It seems to me to make the lens optics that compact will take some special optical trickery, like diffractive optics. If you go to the actual patent you will see other 300/2.8 lens designs which are much more like the EF 300/2.8 ii. The glass in those designs is spread out much more the length of the lens. But an insertable tele converter would not be possible.
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This is the patent diagram aligned with the EF 300/2.8 block diagram at the front element, with the front element diameters matched.
There's about the same amount of glass in the rearward groups (behind the aperture stop). Stronger converging lenses in front of the aperture stop in the patent enable the rearward groups (and the aperture stop itself) to be shifted forward, essentially relocating the empty space that is in front of the aperture in the EF 300/2.8 II to the back. That, combined with the extra space because the patented design is longer (and remember that the flange distance is 24 mm shorter with RF), allow room for the TC elements to drop in. No special optical trickery required.
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I would rather see an RF 500 or 600 f4 with inbuilt extender, as the Nikon Nikkor Z 600mm f/4 TC VR S. Canon should have had this a long time ago, and one reason I would have choosen Nikon today, if I had started at scratch. To just flip in and out the tc is very different from changing a separate TC in field. I guess the quality could gain some steps too.
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Neuro, great you matched the front element diameters. Had that thought but too many other things on the agenda. To my eye there is more curvature to the EF lens front cell, but there is one more element, 8 vs. 7, in the patent lens. The section behind the diaphragm is interesting with more, 10 vs 8, elements but thinner, lighter looking elements. Also, seems to be less curvature to the patent lens elements. And, lastly, my estimate of distance of filter to image plane is a wee bit over 37 mm, which I believe is enough to allow use of the present tele converters.
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you can't take the embodiment diagrams to that level of scale. They are only there to show the rough approximation.
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Not sure why you're talking about Zooms "The problem with 400-600mm zoom designs" as I never mentioned any.
My ideas for these Primes with builtin T.C.s is that they would replace the current 600mm f/4 with a 300mm f/2.0 with 1.4x and 2x builtin T.C.s and
the 400mm f/2.8 with a 200mm f/.4 with 1.4x and 2x builtin T.C.s.
This means you'd still have the option of adding external T.C.s as well i.e:
the 200mm f/1.4 (with internal 1.4x and 2x) gives these options
- 200mm f/1.4
- 280mm f/2
- 400mm f/2.8
- 560mm f/4
- 800mm f/5.6
- 300mm f/2.0
- 420mm f/2.8
- 600mm f/4
- 840mm f/5.6
- 1200mm f/8
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Image quality of a RF300 mm f2 lens + 2 times extender would not be a match for a ‘bare’ 600mm f 4 lens. Same for AF speed and accuracy. Stacking teleconverters will make both even worse.
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A 0x teleconverter is a lens cap.
The rumored 1x-1.4x-2x TC came about from misinterpretation of a patent, such a lens would be extremely complex because the 1x setting would require reducing optics (otherwise, it would be an extension tube and limit distant focusing). So, such a lens would need to have 1x optics and two sets of 1.4x optics that swing in/out. I highly doubt we'll ever see such a product. The patent on which that rumor is based had four elements. Four, with two of them sliding back and forth. It's not what some people seem to think it is.
There was another patent around the same time for a 1.4x-2x switchable TC, that had the second set of 1.4x optics split into two moving groups that swung out of the path. It looked pretty large and unwieldy, and the mythical 1x-1.4x-2 would need to be much more complex.
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It's better than you think. I used to shoot the RF 300mm f/2.8 II with the 2xTCIII and found it excellent. It stands up well, even on Craig's dishonourable 5DSR vs the RF 600mm f4 on the R5. I'm jealous of the Sony 300/2.8 as it gives a very sharp and light 600/5.6.
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I had this lens. It cost $4000 at the time. It weighed about the same as the 600 f4 of the time. It was not as long as the Nikon and Canon 400 2.8s but fatter and heavier. It had a nice screw out hood and an additional hood. Tack sharp as you’d expect. Also, had its own TC-1.4C which retained great image quality. What photographers. today will never will realize about these big tele primes is how incredibly skilled you needed to be to focus them. The depth of field on the 300 f2.0, 400 2.8, and 600 4.0 are nearly the same at most equivalent shooting distance. Very shallow.
Where’s the lens today? I’m not sure. I sold it when I switched to Canon’s EOS in the early-90s. I got a Canon 400 2.8 at that point. I kind of wished I still had it, they fetch a fortune these days.
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