The following came from Stefanie Daniella:
i disagree with your apologetic negative position.
i had long pointed out the EOS R is a mini-EOS C700FF/C500/C300/C200 Cinema camera.
All of the EOS Cinema cameras are speedcrop capable, especially the EOS C700FF.
The huge Professional EOS C700FF has plenty of 1:1 straight-read speedcrop modes, using only a portion of the image sensor, but Canon's prosumer EOS 1DC, 1DXMKII, 5DMKIV, and R, and RP, all have their unique 1:1 straight-read speedcrop mode:
1DC: 1.266x 4k dci + 1.350x (16:9) 3.8k
1DXMkII: 1.336x 4k dci + 1.425x (16:9) 3.8k
5DMkIV: 1.641x 4k dci + 1.750x (16:9) 3.8k
EOS R: 1.750x (16:9) 3.8k
EOS RP: 1.63x [1.625x 1.003x] (16:9) 3.8k
EOS M50: 2.522x [1.5625x 1.614x] 3.8k
In order for C700FF to get 1:1 straight-read:
it runs 5.95k dci FF, it's a 0.945x factor-wide, and only lower-rez 4k/2k dci is "downsized oversampling" full-sensor-width
it also runs 5.58k 16:9, it's a 1.008x speedcrop, and only lower-rez 3.8k/1.9k (16:9) is "downsized oversampling" crop-sensor-width
and 1:1 straight-read speedcrop modes with 2.748x speedcrop 2k dci, and 2.927x 1.9k (16:9) fhd
or other EOS C700/500/300/200 run in various other S35 speedcrop modes:
C700 S35: 1.343x 4k dci
C500/C300/C200/C100 (S35): 1.374x 4k dci
C500/C300/C200/C100 (S35): 1.463x 3.8k (16:9)
Others like Sony's CineAlta Venice FF have 1:1 straight-read 1.4815x speedcrop 4k dci, and 1.5789x speedcrop 3.8k (16:9), too; which is its default "already-paid" feature; in order to use higher 1.003x "no crop" FF 6k or 1.068x 5.7k, one must pay EXTRA $$$ for license to enable it!
Unfortunately, Sony's consumer Alphas do NOT get true 1:1 straight-read speedcrop 3.8k 16:9 (4k uhd), and only get amateurish toy low 100Mbps (excessively) "downsized oversampling" from overhyped "full-sensor-width" (as if it's superior to 1:1 straight-read!!!); with such amateurish pedestrian 100Mbps, colors are worst in 3.8k possible. And consumer Sony Alphas avoid faster higher Mbps because it already is premature overheating-prone at only 100Mbps! (It's woefully poorly heatsinked floating jiggly-shuttershock-prone sensor-shift based IBIS is needed, because Sony has WEAKEST almost-live-view almost-autofocus in the "mirrorless-only" industry.)
Even when Sony Alphas "downsize oversampling" on full+crop-sensor-width modes, it's never 1:1 straight-read either: too much image processing is WASTED TOSSING RESOLUTION to get downsized to 3.8k and 1.9k!!! A9 is the only 1.200x speedcrop 1:1 straight-read, but at amateurish toy-like pedestrian low maximum 100Mbps, too. (useless in sony users hands).
Anyone familiar with advantages of higher speedcrops, knows one can have wide-angle FoV with proportionately high speedcrop factor brighter faster aperture with deeper dof that produces MORE DETAIL than "no crop 1.0x" 3.8k "full-sensor-width" heavily downsized oversampling from 6k, 7k, tossed to get only 3.8k or 1.9k!!!
The easiest way to compare "Fov+DoF" (like-vs-like), one can use the popular 10mm FL lens across all possible speedcrops on cinema cameras, to demonstrate advantages of faster brighter deeper dof more detailed 3.8k (4k uhd)
4k uhd (3.84k)
Deep DoF: 1.5mm Aperture Diameter (compare EXACTLY same dof-vs-dof)
Comparing EXACT same FoV-vs-Fov (Exact same AoV-vs-AoV)
10.0 mm 1.750x speedcrop = 17.5mm F6.67 FF.FoV EOS R (480Mbps) 5.36um = 1.750x brighter faster f-stop!!!
17.5 mm 1.000x "no crop" = 17.5mm F11.67 FF.FoV Sony Alpha FF (100Mbps) 4.5um or 5.93um ... 1.750x darker f-stop !!!
10.0 mm 1.63x speedcrop = 16.3mm F6.67 FF.FoV EOS RP (120Mbps) 5.76um = 1.63x brighter faster f-stop!!!
16.3 mm 1.000x "no crop" = 16.3mm F10.86 FF.FoV Sony Alpha FF (100Mbps) 4.5um or 5.93um ... 1.63x darker f-stop !!!
Pick ANY/ALL other of your Favorite FL for SAME FF.FoV, and you face SAME speedcrop advantage!
with highest detail for 4k uhd (= deepest dof) = 1.5 mm aperture diameter!): like-vs-like (Exactly SAME FoV+DoF)
13.7 mm 1.750x speedcrop = 24.0mm F9.1 FF.FoV EOS R (480Mbps) 5.36um = 1.750x brighter faster f-stop!!!
24.0 mm 1.000x "no crop" = 24.0 mm F16.0 FF.FoV Sony Alpha FF (100Mbps) 4.5um or 5.93um ... 1.750x darker f-stop !!!
14.7 mm 1.63x speedcrop = 24.0 mm F9.8 FF.FoV EOS RP (120Mbps) 5.76um = 1.63x brighter faster f-stop!!!
24.0 mm 1.000x "no crop" = 24.0 mm F16.0 FF.FoV Sony Alpha FF (100Mbps) 4.5um or 5.93um ... 1.63x darker f-stop !!!
Ditto: ALL FL (All lenses) covering IDENTICAL FoV+ DoF! (Pick ANY Favorite FoV and Favorite DoF Aperture Diameters!)
Higher Speedcrops offer MORE DETAIL (DEEPER DOF!) at FASTER BRIGHTER F-VALUES in PROPORTION to SPEEDCROP FACTOR!
If you NEVER heard of "Speedcrop", that's okay, because it is a TERM that simply SUMS UP in ONE WORD, what's demonstrated in the above explanation.
For EVERY/ANY/ALL Identical FoV+DoF "look" (like-vs-like) for MAXIMUM DETAILS (why 4k uhd is used instead over 1080p), lacking high speedcrop advantage ALWAYS means poorer Image Quality whether under bright lit or low-light lit scenarios, STUCK with darker slower f-values, thus the otherwise unnecessary need for longer slower shutterspeeds. By the time one hits widest-apertures of lenses, one is on the shallowest wider open apertures where the LEAST DETAILS is the norm; which defeats the point of even using higher 3.8k rez over lower-rez 1.9k (1080p).
(If you don't "get it" ... then you're easy prey for the ludicrous hype of downsizing oversampling from either full-sensor-width or crop-sensor-width COMMON on other's 3.8k using toy consumer level low Mbps Sony FF/APSC Alphas, LACKING FASTER BRIGHTER HIGHER SPEEDCROP FACTOR ADVANTAGE. It's NO SURPRISE that SONYS cannot Autofocus properly with deep dof apertures, whether on CineAlta Venice or Alphas, using OEM Sony AF F/E Lenses!