Patent: Canon is actively developing fast mirror lenses

entoman

wildlife photography
May 8, 2015
1,400
1,754
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Long reach and fast aperture make it sound like this would be a great and possibly lightweight choice for birding, but as soon as you have a close nervous background such as branches, stalks, or grass, the donut bokeh can really punishing.
For birding or any other nature photography where depth of field is narrow, pleasing bokeh is an absolute must. Even with a conventional tele or zoom I've had many shots ruined by ugly bokeh on branches, foliage or specular reflections from water. So while lightweight wide-aperture lenses have an appeal, I wouldn't consider using a catadioptric.
 
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neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
28,090
8,303
They keep releasing F4 and F5 lenses while their competitors release F1.2 and F 1.8. Will just continue using my EF lenses with the adspter booster. They work.
This is a patent application, nothing in it has been released. The RF 135/1.8L IS starts shipping today. Try to keep up with reality.
 
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Juangrande

EOS RP
Mar 6, 2017
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Regarding to the RF 800 f/11, my EF100-400 Mk2 with the MkIII 2x extender has equal focal length at the long end, without any significant IQ difference. So I do not see any benefitial step up from the RF800 f/11 to my current EF lineup. And for me, from the 1400-2000mm is the regulary used focal length, not the 800mm. The 1400-2000mm is the right tool for the contrail spotting, but the noise level is quite high because the lack of IS. The 100-400 and the extenders are for the airshows, where I have to shoot on both the close taxiing aircraft throught out the whole demo box airspace, with the smae equipment. That's why I do not see any relevant purpose for the fix 800mm f/11 lens.
You could use a tripod with a quick, agile video pan head in leu of IBIS or even a monopod to be able to shoot at a lower iso. What’s the slowest shutter speed you can shoot at in your scenario?
 
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AlanF

Desperately seeking birds
CR Pro
Aug 16, 2012
10,504
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Regarding to the RF 800 f/11, my EF100-400 Mk2 with the MkIII 2x extender has equal focal length at the long end, without any significant IQ difference. So I do not see any benefitial step up from the RF800 f/11 to my current EF lineup. And for me, from the 1400-2000mm is the regulary used focal length, not the 800mm. The 1400-2000mm is the right tool for the contrail spotting, but the noise level is quite high because the lack of IS. The 100-400 and the extenders are for the airshows, where I have to shoot on both the close taxiing aircraft throught out the whole demo box airspace, with the smae equipment. That's why I do not see any relevant purpose for the fix 800mm f/11 lens.
My comment was meant that the 800mm f/11 was for your use on your 8th floor balcony, not as a general purpose walk around lens. When I go out, I normally take the RF 100-500 or RF 100-400 + TCs with me unless I know it's for long distances only when I'll sometimes take out the 800mm f/11.
 
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You could use a tripod with a quick, agile video pan head in leu of IBIS or even a monopod to be able to shoot at a lower iso. What’s the slowest shutter speed you can shoot at in your scenario?
Tripod is not an option for a contrail or even for a long distance aircraft photography, due to the very narrow field of view, combined with the realtive position of the target and the relatively fast moving target. Just imagine to make a photo with 2000mm about a continously moving airplane, what you have to find by your own naked eye first. A video pan head has its own initial angle limitation, which is really slows down the reaction time. Previously, I made a photo about the ISS with the single f/10 1000mm mirror lens, handheld, because of the position of the object (right above my head, on the Zenith). So these circumstances are not really god for a tripod-related photography. I also tried a monopod, but was not so helpful at all. The slowest shutter speed ever was 1/640, but the finest sweetspot is around 1/1000 - 1/1250, depending on the actual relative angle and position of the path of the aircraft. And the shutter speed is crucial, since the reflex mirror has a lack of sharpness, combined with a really narrow depth of field. And the fact, that you could rotating over the infinite distance mark the tube, you could easly miss the right focal point. By a native 1000mm mirror focal length (the extenders are really does not matter) the depth of field is extremly narrow, so between an 1000 or an 1500 meter, I have to set the focus, with the possibility of the overrotating.
 
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unfocused

Photos/Photo Book Reviews: www.thecuriouseye.com
Jul 20, 2010
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Question: Do mirror lenses stop down? I was under the impression that the aperture was fixed on a mirror lens and the only option was to use ND filters.

Comment: Since the main advantage of mirror lenses is light weight and small size, I'd rather see a longer option, such as mentioned in this rumor.
 
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usern4cr

R5
CR Pro
Sep 2, 2018
1,301
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To me, a good (& obvious) use for a lens of this type would be for astrophotography since you focus at infinity and nothing is supposed to be OOF. Getting the f# to be really fast while keeping sharp star points at infinity across the entire sensor would be quite worthwhile for that narrow usage. But for general photography, I see the value just as an inexpensive & compact way to get a long fast lens for those that don't care about the terrible OOF blur quality.

The only time I saw a quality unobstructed (tilted) folded optical design with stellar IQ was the Stevick-Paul telescope design. It uses 3 spherical mirrors and no lenses and results in a tilted (and slightly curved) image plane. But it is not a fast design and is very large relative to the aperture size. Some ambitious amateur telescope makers (grinding their own mirrors) have delved into this.
 
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Dragon

EF 800L f/5.6, RF 800 f/11
May 29, 2019
723
786
Oregon
Regarding to the RF 800 f/11, my EF100-400 Mk2 with the MkIII 2x extender has equal focal length at the long end, without any significant IQ difference. So I do not see any benefitial step up from the RF800 f/11 to my current EF lineup. And for me, from the 1400-2000mm is the regulary used focal length, not the 800mm. The 1400-2000mm is the right tool for the contrail spotting, but the noise level is quite high because the lack of IS. The 100-400 and the extenders are for the airshows, where I have to shoot on both the close taxiing aircraft throught out the whole demo box airspace, with the smae equipment. That's why I do not see any relevant purpose for the fix 800mm f/11 lens.
An Olympus ee-1 red dot finder would be very helpful for target location in your situation. I have most of the better mirror lenses that were made, including the Nikon 1000mm and the Canon, Minolta, Tamron, and both Nikon designs at 500mm. I would agree that adding a TC doesn't lose as much as you would expect (particularly on the Nikon 1000mm), but the RF 800 f/11 sill gives more detail than any of the mirrors. An Rf 800 f/11 with a 1.4 TC on an R7 will give you very close to the same number of pixels on target as 1400mm on the 7D II and the combination of AF and IS makes the likelihood of getting the shot about 1000 times higher. I have a lot of fun with mirror lenses, but for serious work, the 800 f/11 is in a completely different league. I posted some examples here https://www.canonrumors.com/forum/t...-first-half-of-2023.42023/page-10#post-950943 . Note that the mirror shot and the 800 f/5.6 L shots were both from a tripod and the 800 f/11 shot was handheld, and I do use the ee-1 finder on all the long lenses.
 
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An Olympus ee-1 red dot finder would be very helpful for target location in your situation. I have most of the better mirror lenses that were made, including the Nikon 1000mm and the Canon, Minolta, Tamron, and both Nikon designs at 500mm. I would agree that adding a TC doesn't lose as much as you would expect (particularly on the Nikon 1000mm), but the RF 800 f/11 sill gives more detail than any of the mirrors. An Rf 800 f/11 with a 1.4 TC on an R7 will give you very close to the same number of pixels on target as 1400mm on the 7D II and the combination of AF and IS makes the likelihood of getting the shot about 1000 times higher. I have a lot of fun with mirror lenses, but for serious work, the 800 f/11 is in a completely different league. I posted some examples here https://www.canonrumors.com/forum/t...-first-half-of-2023.42023/page-10#post-950943 . Note that the mirror shot and the 800 f/5.6 L shots were both from a tripod and the 800 f/11 shot was handheld, and I do use the ee-1 finder on all the long lenses.
Interesting. Thank you, this could be a good new direction for me, even if I said different before. I have to re-thinking my approach. However, I have no extra money for the R7, but for its successor, maybe.
 
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Dragon

EF 800L f/5.6, RF 800 f/11
May 29, 2019
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Oregon
An IS section is not obvious in the diagram, but focusing with the second group rather than moving the primary mirror is quite different from most mirror lenses and could make AF much faster. Also, the very close spacing between the front element and the primary mirror is unique. This is the second patent where Canon is pushing the secondary optics out behind the primary mirror. the last one produced an upright image, but this one is still inverted (as normal).
 
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photophil

In therapy for GAS
Jun 17, 2022
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Question: Do mirror lenses stop down? I was under the impression that the aperture was fixed on a mirror lens and the only option was to use ND filters.

Comment: Since the main advantage of mirror lenses is light weight and small size, I'd rather see a longer option, such as mentioned in this rumor.
There are few that do, but not unheard of. Most are indeed fixed aperture though.
 
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David - Sydney

EOS 5D Mark IV
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Dec 7, 2014
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Currently, next to me, on my Canon 7D Mk2, a large 1000mm MTo 10/1000 is sitting on a top of a Canon EF 1.4x MkIII extender. The image quality with this extender is almost identical as without it, so as the noise level on the f14 aperture. This manual focus 1400mm mirror lens is a quite good toy for the long distance aircraft spotting from my 8th floor balcony. I just need an IBIS and I would be 100% happy :)
I believe that IBIS would have a limited benefit for long focal lengths vs built in lens IS.
 
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Dragon

EF 800L f/5.6, RF 800 f/11
May 29, 2019
723
786
Oregon
I believe that IBIS would have a limited benefit for long focal lengths vs built in lens IS.
True. I have a similar Cat lens setup and IBIS helps a bit with exposure if you set it to only work during the exposure, but it doesn't help that much. Also, 1000mm is as long as you can set the IBIS for a manual lens (at least on Canon bodies). The IBIS doesn't help at all for VF stability as an aid to manual focus.
 
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EOS 4 Life

EOS 5D Mark IV
Sep 20, 2020
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