Greetings,
These are all good questions, but we really need to know more about the intended use for your camera.
The lack of IBIS on the R5 C has not been a detriment for me. All of my lenses have image stabilization. I've not had any issues shooting, handheld or using a tripod in low light when using a fast lens with IS. Similarly, great video can be shot handheld or when using a gimbal with very good results.
The IBIS system on the R6 mkIII provides up to 8.5 stops at the center of the frame and up to 7.5 stops in the periphery.
Recording times. The R6 mkIII can record 7K open gate in 73° weather for about 23 to 36 minutes. Factors affecting recording time: Frame rates. Also how hot the camera is before you start recording. Whether or not you are using external USB-C for power and/or have any wireless features enabled. These times are for internal recording to the CFB card. The R6 mkIII can output 7K 30 over HDMI to an external recorder but it is still susceptible to overheating.
On the R5 C 8K RAW, the camera doesn't shut off. You are really only limited by media capacity and power. I have never had the camera shut off or not been able to turn it on due to heat. The warmest temperatures I've ever shot in was Montana Summer in July. It was about 89° . The fan in this body allows it to shoot continuously unlimited.
I think the R6 mkIII is going to be a real home run for Canon. You can pretty much shoot 4k 30 nearly unlimited and 4k 60 fine for about 30 min depending on temperature and humidity. Recording time will be directly impacted by ambient temperature . Do not expect it to run in 7K for longer than about 23 minutes.
R5 C. I don't shoot in 8k. It was never my intention but you can if you want to. The camera will not overheat. I haven't seen any documented instances of overheating with this camera. Nor have I ever experienced a heat related limitation.
I am a hybrid shooter. Stills and video. I chose the R5 C because I wanted a camera that I could count on no matter what. I'm happy to say I got that.
If I was looking to shoot unlimited 7K VR, the C50 would probably be a great way to go. I need a viewfinder though.
The R6 mkIII strikes a great balance for someone looking to shoot wildlife and video. If you need 7K 30/60 unlimited, I would not choose this camera. Instead, go for the R5 C.
~Rick
Bay Area - CA
~R5 C (1.1.2.1), ~R50v (1.1.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, ~RF 200-800 +RF 1.4x TC, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve Studio ~ImageClass MF644Cdw/MF656Cdw ~Pixel 10 ~CarePaks Are Worth It
