A bit of history about Canon and catadioptric (mirror) lenses

pape2

EOS 90D
Mar 19, 2021
117
147
Needing teleconverter if shooting big butterflyes with 5200mm .
and something like this to push it around.
 
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Reactions: chasingrealness
Apr 2, 2014
8
4
Victoria, Australia
I still have my FD500 f8 reflex lens, works well with a cheap FD to EF adapter: sadly no AF or IS in 1985. Doesn't get a lot of use but am happy to see the possibility of new reflex/cat lenses coming.
Supermoon-1.jpg
 

AlanF

Stay at home
CR Pro
Aug 16, 2012
8,259
10,327
Needing teleconverter if shooting big butterflyes with 5200mm .
and something like this to push it around.
Its minimus focal distance is 120m. So, it will give you the equivalent of the magnification of a 520mm lens at 12m. So, a 2x TC will be needed, or better still a 4x.
 
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Cochese

EOS 90D
Oct 22, 2014
149
93
And if you adapt your 5200mm to an APS-C camera...

Or, and here me out, attach it to a high megapixel full frame. And then crop. Same effect, more raw image to work with.

You're not adding reach to your images, only cropping the full frame.

Unless both your full frame and crop sensor are the same resolution, anyway.
 

RunAndGun

EOS RP
CR Pro
Dec 16, 2011
451
138
I am not sure that I would trust selling something worth $50K on eBay.

I’ve actually seen way more expensive things on eBay. YEARS ago, in the live(TV) sports world, there were two main companies that provided the wireless transmission services for the handheld cameras and other remote/robotic cameras. At one point, the smaller company failed and was put up for sale. I about fell out of my chair one day when I was looking around on eBay and the company was listed for sale on an eBay auction.
 
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jvillain

EOS RP
Sep 29, 2018
264
209
I wonder how 2000mm f/11 would work for shooting action sequences on bright days with modern low noise cameras. Got to think you would get all the lens compression you will ever need with out the need for a ton of ND.
 

LDS

EOS 5D Mark IV
Sep 14, 2012
1,715
248
What it interesting is Canon is no longer using the old Maksutov-Cassegrain design of those lenses, which was cheaper than the Schimdt-Cassegrain one, not using the aspherical front element. It looks inspired by recent Busack-Honders-Riccardi designs, with the reflective coating on the mirror back instead its front surface, and the positive front lens.

So it looks Canon did some real new researches and designs for these lenses.
 
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Dragon

EF 800L
May 29, 2019
465
437
If Canon brings out some cat lenses, I hope they're a bit lighter than these puppies!
1f601.svg
I kinda remember the Nikon cat lens (for F models), and it was comfortably light (hand-holdable) at 500mm.
The Canon FD 500mm Cat is lighter than the Nikon and quite usable on an R5 with IBIS on. It is also pretty reasonable on fleabay.
 

EOS 4 Life

EOS R
Sep 20, 2020
853
690
I wonder how 2000mm f/11 would work for shooting action sequences on bright days with modern low noise cameras. Got to think you would get all the lens compression you will ever need with out the need for a ton of ND.
I am obviously a Canonite but I also use micro four-thirds because I swore off heavy telephoto lenses.
However, I have not seen micro four-thirds lenses longer than 800 mm.
2000 mm with APS-C would blow micro four-thirds out of the water.
There is still a sweet spot for micro four-thirds with telephoto zooms since the extra crop increases the zoom range.
After that, the main advantage is IS.
Only the R5 and R6 rival my G9 in image stabilization at twice or three times the price.
 

JoeDavid

Unimpressed
Feb 23, 2012
200
61
I still have my FD500 f8 reflex lens, works well with a cheap FD to EF adapter: sadly no AF or IS in 1985. Doesn't get a lot of use but am happy to see the possibility of new reflex/cat lenses coming. View attachment 197632
Yea, back in film days I had a 500mm f8 Tokina lens that was quite sharp. It was compact enough that no one thought it was a 500mm lens. Once you get over the donut bokeh, one with autofocus would be welcome in my kit. I wish Canon had used a reflex/cat design with the 600 and 800 lenses. They could have been smaller and faster. Those are stuck at f11. I’d rather be stuck at f8.
 

AlanF

Stay at home
CR Pro
Aug 16, 2012
8,259
10,327
I am obviously a Canonite but I also use micro four-thirds because I swore off heavy telephoto lenses.
However, I have not seen micro four-thirds lenses longer than 800 mm.
2000 mm with APS-C would blow micro four-thirds out of the water.
There is still a sweet spot for micro four-thirds with telephoto zooms since the extra crop increases the zoom range.
After that, the main advantage is IS.
Only the R5 and R6 rival my G9 in image stabilization at twice or three times the price.
Micro 4/3 may have a crop factor of 2 over FF but the resolution of the G9 sensor isn't two times higher than that of the R5 because of the much higher pixel density of the FF. The pixel pitch of the G9 is 3.32 µ compared with 4.38 µ for the R5, which means the G9 has only 32% more "reach". The 90D and M6II both outresolve the G9 or Olympus equivalents.
 
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SteveC

R5
CR Pro
Sep 3, 2019
2,332
2,185
Or, and here me out, attach it to a high megapixel full frame. And then crop. Same effect, more raw image to work with.

You're not adding reach to your images, only cropping the full frame.

Unless both your full frame and crop sensor are the same resolution, anyway.

Yes. "Reach" depends on pixel density and focal length, not the size of the sensor. Of course if it's a big sensor you end up having to crop in post (or use the crop mode if the camera has one) but you still get the same results as you would with a smaller sensor of the same density.

That being said, crop sensors tend to have a higher pixel density, so it's easy enough to get a little lazy just equate them with better reach because of the APS-C sensor. And as far as I know the best pixel density Canon has to offer is on the M6-II and the 90D. The R5 has the same density as a (hypothetical) 17MP APS-C camera. Not so long ago that would have been killer megapixels, today the APS-C birders and the like find it a step down, and it actually is, from their 7Ds.
 

EOS 4 Life

EOS R
Sep 20, 2020
853
690
Micro 4/3 may have a crop factor of 2 over FF but the resolution of the G9 sensor isn't two times higher than that of the R5 because of the much higher pixel density of the FF. The pixel pitch of the G9 is 3.32 µ compared with 4.38 µ for the R5, which means the G9 has only 32% more "reach". The 90D and M6II both outresolve the G9 or Olympus equivalents.
While you are correct, I do also have an R5 which makes me use the G9 less but Panasonic MFT lenses are much smaller for the same reach.
The main point of my comment was that advantage is getting less and less but it does still exist.
MFT and RF have the exact same flange distance and MFT is smaller so I am not sure why there is no MFT to EOS R adapter.
I guess maybe the size difference is not enough to fit an MFT adapter into an RF mount.
 

CanonFanBoy

Purple
CR Pro
Jan 28, 2015
5,566
3,965
Irving, Texas
While you are correct, I do also have an R5 which makes me use the G9 less but Panasonic MFT lenses are much smaller for the same reach.
The main point of my comment was that advantage is getting less and less but it does still exist.
MFT and RF have the exact same flange distance and MFT is smaller so I am not sure why there is no MFT to EOS R adapter.
I guess maybe the size difference is not enough to fit an MFT adapter into an RF mount.
If they have the same exact native flange distance, doesn't adding the adapter change the flange distance from lens to sensor? Absolutely. That is probably why there is no adapter. The reason EF to RF works is because EF lenses have a naturally greater flange distance than RF. So adding the adapter makes up for that. So, to me, this is the same reason RF isn't adapted to EF. You increase the flange distance with an adapter.

*I have no idea what the flange distance measurement is for MFT vs RF.* Just assuming @EOS 4 Life is correct. :)
 
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Del Paso

M3 Singlestroke
Aug 9, 2018
1,185
1,253
If they have the same exact native flange distance, doesn't adding the adapter change the flange distance from lens to sensor? Absolutely. That is probably why there is no adapter. The reason EF to RF works is because EF lenses have a naturally greater flange distance than RF. So adding the adapter makes up for that. So, to me, this is the same reason RF isn't adapted to EF. You increase the flange distance with an adapter.

*I have no idea what the flange distance measurement is for MFT vs RF.* Just assuming @EOS 4 Life is correct. :)
Sometimes it works!
A Spanish company (Leitax) replaces Nikon F bayonets with EOS EF ones, or Leica R's with EF bayonets, so there's no need for an adapter which, as you mentioned, adds flange distance. Due to the high precision manufactoring of these bayonets, F Nikons or R Leicas work perfectly well on EOS DSLRs (with RF-EF adapter also on EOS R).
Of course, would adapting MFT to RF make sense??? That is the question...
 

EOS 4 Life

EOS R
Sep 20, 2020
853
690
If they have the same exact native flange distance, doesn't adding the adapter change the flange distance from lens to sensor? Absolutely. That is probably why there is no adapter. The reason EF to RF works is because EF lenses have a naturally greater flange distance than RF. So adding the adapter makes up for that. So, to me, this is the same reason RF isn't adapted to EF. You increase the flange distance with an adapter.

*I have no idea what the flange distance measurement is for MFT vs RF.* Just assuming @EOS 4 Life is correct. :)
There is no glass in the adapter so it would not necessarily increase the flange distance.
It would just be one mount inside of another.
The diameter seems like a bigger challenge because the adapter would need to connect to the RF pins while at the same time having the MFT pins for lenses to connect to.
 

20Dave

EOS M6 Mark II
CR Pro
Jan 19, 2013
74
55
I wonder how these Canon lenses would compare with the equivalent telescopes. The Celestron Edge line of scopes (see here) would be one of the competitors. One big difference would be the mounting assembly. Telescopes typically come with dovetail bars to attach to astro mounts rather than tripods.