Canon R5 or R5C?

Ken Ross wrote:

Regarding the two disadvantages of the R5c relative to the R5, I can comment on the actual real world differences (and provide examples above) since I actually own and have used both cameras.

IBIS- Although the R5c does not have IBIS, the overwhelming level of stabilization with OIS equipped lenses comes from the OIS. Using exactly the same RF24-240 & RF100-400 on both cameras, I have found the difference in the stability to be of no great significance.

But what about non-OIS lenses? My only non-OIS lens is the RF50mm. By switching on even the lower level of the two available electronic IS settings, the stabilization is very good. The only price you pay is a slight degree of crop. In situations like this internal IBIS would be preferable if you wish to avoid any crop, but the results are still very good.

AF- The biggest difference I have found is the absence of animal AF. However in day to day usage I have not found significant differences in the overall AF performance.

The video above was shot all handheld, with the R5c, using the RF100-400. AF was used exclusively. Many shots were close to or at 400mm. This is not only a significant test of the AF with animal subjects, but also of the real world stabilization when using OIS lenses. I would be happy to provide examples of the non-OIS 50mm lens coupled with the electronic stabilization of the R5c. Again, IBIS would be preferable, but the degree of difference is simply not the great with OIS equipped lenses. The electronic IS is there for non-OIS lenses if needed.

To make this very clear: IBIS has no effect on lenses above 100mm. So, your experience with the 100-400mm OIS lens is exactly right - the R5 has no advantage. But, it is mostly irrelevant for video shooting: below 100mm you cannot use non-OIS lenses without IBIS shooting handheld without digital stabilization, which crops and reduces resolution. And digital stabilization I believe is unavailable for RAW video, which is a major feature of the R5 variants (correct if wrong). Most videography is done with lenses below 100mm, and almost all cinema lenses do not have OIS. Of course, most cinema shooting is not handheld without gimbals. And IBIS+an OIS lens, below 100mm, gives you amazing undegraded stabilization, since they work in tandem.

Here is a handheld 8K RAW video shot with the Canon RF 16mm non-OIS lens.  You do not want to crop it with degrading digital stabilization (if it were possible in RAW), and lose the nice wide-angle. This video thus could not be shot with the Canon R5 C. There is no handheld video that cannot be shot with the R5 that the R5C could shoot.