Patent: Lots of fast RF prime lens optical formulas

tron

EOS R5
CR Pro
Nov 8, 2011
4,690
917
Also I do have Sigma 14 1.8 and it works just fine with EF-RF adapter on my EOS R so say a 3K Canon 14 1.8 would have a competition.
 
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Rivermist

Mirrorless or bust.
Apr 27, 2019
64
91
Houston
Finally 135 mm update.

85 madness, sounds like canon can't get over it.
Agreed, while 85mm is a key focal length I find 135mm to be the ideal portrait and mid-telephoto lens, making more sense as a prime since 85mm is included in most mid-zooms (close to the 70mm of a 24-70, inside the 24-105 bracket), whereas if I want to have the mid-zoom + 2 large(r) aperture primes then a 24, 28 or 35mm prime + a 135mm prime provides an expansion of the available focal lengths associated with the 24-70 or 24-105.
Hopefully these primes will have IS so that I don't have to buy the R6 (yet) to get IS.
An aperture of f:2.0 is good enough, I would not want the lens to be a monster, otherwise one might as well get the RF 70-200L IS 2.8.
I owned and loved the EF 135 f:2, and also many years ago the FD 135mm f:2.5. Both allowed for great intimate pictures of people and creative street photography.
 
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Rivermist

Mirrorless or bust.
Apr 27, 2019
64
91
Houston
What I don't see to grasp (and I hope somebody does know the answer) is the proclaimed benefit of the new mirrorless mounts (both Canon and Nikon). We've been told that the new mounts can results in new/better optical formulas. We haven't seen any "extremes" however. Yes, ofcourse we now have the 600mm and 800mm F11 which weren't possible with DSLR autofocus sytems, but besides that, most that is offered in RF mount is also available in EF. Does somebody know and could please explain what the real world benefits of these new mounts are?
Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. (https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).
 

Franklyok

EOS M6 Mark II
Oct 24, 2018
91
35
Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. (https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).
As long as there is no patent to 70-135, there is no hope.
 

tron

EOS R5
CR Pro
Nov 8, 2011
4,690
917
Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. (https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).
RF 15-35 2.8L IS yes and I got it but Tamron has already IS so it can be done in EF mount
RF 24-70 2.8 L IS ditto for Tamron in EF mount and Nikon in F mount (the 24-70 2.8E VC)

The 15-35 is NO better than 16-35 2.8L III (and unfortunately It has the same vignetting)

The 50 1.2 and 85 1.2 are definitely better in RF version but the EF versions were very old designs so I believe Canon could improve them if they wanted to.

Canon EF L lenses were/are very good so to me it is the trend that makes them go to the mirrorless direction.
 
Aug 29, 2020
5
1
Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. (https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).
Thanks for the explanation. It makes a lot more sense now. As far as I understand is that the enhancements by the RF mount mostly result in increased image quality. About that RF 70-200mm, the fact that it is a pumper zoom put me off from it. Had the Nikon 200-500mm F5.6 which is a pumper zoom as well and it got quite dirty inside when you use it a lot outdoors. The possibility of placing larger elements more to the back with the RF mount makes me quite interested in what a RF 400mm F2.8 or 600mm F4 can shave off in weight. Both Sony and Canon have managed to shave quite some weight off of their latest super long telephotos by placing the elements more to the back and therefore be able to shrink them quite significantly.