As reference, I’m a professional videographer whose footage has been featured in numerous network science/nature/educational documentaries and museum exhibits worldwide. I specialize in extreme macro, micro and tele footage.
The Sony A7R III is an awesome camera and clearly beats out the Canon 5D Mark IV when it comes to shooting 4k video. I really wanted to love the Canon because I’ve been shooting with the 5D Mark II and the 7D for close to 10 years and own a slew of Canon glass and accessories but had to return it after trying the Sony. Here are Sony’s 3 big advantages over the Canon for 4k video:
1. Sony shoots in an efficient codec that creates files that are 1/5 the size of Canon’s. That means I can buy a lot less memory cards and storage drives saving close to a thousand dollars out the door, not to mention the time saved in downloading, etc. The Sony shoots at a bit-rate of 100/Mbs which means I don’t absolutely need a new computer or external graphics card to play back footage smoothly like I’d need for the Canon.
2. Sony has an optional 1.5 crop factor that enables me to zoom into a subject with the push of a button with undetectable loss of quality. The Canon has a 1.64 crop factor that is NOT optional. You are stuck with it in 4k. That turns a 24mm lens into about a 40! That required me to purchase Canon’s 16mm to 35mm lens to compensate. Sony has an additional feature that gives you an extra 1.5 zoom factor which gives impressive telephoto/macro results, and believe me, I’m very picky.
With the Sony I can effectively turn a 400mm lens into 900mm with no apparent deterioration. (Can you imagine how much a native 900mm lens would cost?!) I can achieve an effective 1,260mm when I add a Canon 1.4 extender, with virtually no loss in in quality!) BTW, while many reviews site an additional 1.2 crop on the Sony when shooting at 30 fps, that only applies to the A7, NOT the A7R which uses a different (42 MP) sensor. There is NO additional crop difference between shooting 30 fps or 24 fps on the A7R.
3. Rolling shutter “jello-cam” artifacts are minimal on the Sony while they are quite severe on the Canon. This opens up more shot possibilities for the Sony.
Bottom line, Canon has been resting on its laurels since the introduction of the 5D Mark II (where did that genius go–was it a fluke?) and can no longer compete with Sony I regret to say. I get the sense that the Sony A7R is much more of a video camera, while video is becoming an afterthought for the Canon DSLR line. Sony has zebras, peaking, time code generation and external 4k recording; Canon does not. Sony shoots 120 fps at 1080; Canon can only do 60fps at 1080. Being mirrorless, I can actually look through the viewfinder on the Sony while I’m shooting which is great for bright light conditions; not so the Canon which requires a 3rd party viewfinder like the Zacuto when shooting in bright light.
Sony has a titling LCD screen; Canon’s is fixed. I can run an external monitor from the Sony without losing picture on Sony’s LCD screen or viewfinder; the Canon LCD shuts off when connecting to an external monitor so there’s no sharing with another crew person. Sony has S-log AND HLG; Canon has only C-log. (One hit on the Sony as far as S-log and HLG, though, is that the milky images typical of uncorrected log gamma are difficult to see on the Sony LCD/viewfinder, while the Canon has a feature, if you select it, that enables you to see enhanced color and definition on the LCD even when shooting in C-Log. I have not found such a feature on the Sony.
I should point out that the Sony A7R does NOT have anti-aliasing, which results in sharper images which I love, but also leads to moire artifacts in some subjects. The Canon has A.A. which practically eliminates moire artifacts, but at the expense of very slightly reduced sharpness. (Why can’t Canon and Sony have optional A.A. so you can pick when you need it?)
BTW, I’m keeping all my Canon glass, etc., and using a Metabones adapter, which loses some lens functionality, but I’ve always shot manual anyway, so this is not a big concern. I will also keep the awesome Canon 16-35 wide angle zoom for my gimbal work. This is the brightest, sharpest lens I’ve owned and I own a lot of other Canon L lenses.
There is still much to love about the Canon 5D Mark IV — the look, the rugged feel, the build quality, easy menu navigation, larger buttons, the exceptionally bright LCD/viewfinder, the robust built-in time-lapse capability, the fact that it is true 4k, not UHD like the Sony — and this has not been an easy decision, but since 4k is my bread and butter, I had to go with the Sony. I’m still hoping Canon will eventually introduce a DSLR or mirrorless camera that can compete with the A7R in 4k.
BTW, some argue that Canon has purposely crippled the 5D Mark IV so it won’t compete with their cinema line. That makes no sense to me since it really only pushes people (like me) toward equivalent priced but superior cameras like the Sony A7R. Wake up, Canon!
Tested against my med format leaf back
I have shot interiors with a Leaf altus CCD back for 10 years and I tested this sensor and found that my Leaf rolls off in the highlights more smoothly and holds more detail on normal exposures. The Sony is so much less noise in the shadows that I can under expose by 2 stops and get the highlight detail with smoother shadows. With regret I have transitioned to the Sony.