I like these developments. Canon's move into mirrorless provides welcome competition to Sony, will prevent Sony from resting on its laurels and will eventually provide a true alternative system.
They've done a very good job with the lenses so far, making needed, core lenses first, of good optical quality and, just as importantly, good manufacturing consistency (a persistent Sony weakness), without too many oddball, fringe lenses. (I actually like the telescoping 70-200 design - it can fit into the same space as a standard zoom or prime in a backpack, instead of taing up two 'slots'). Their bodies haven't so much been weak as they have been entry-level - so far, they've released mirrorless updates to the 6D and competitors to previous-generation Sony bodies (which are still made/supported/in-stock, sold at a discount and basically serve as Sony's 'entry level'), without a competitor to the A7r3/4 and A9i/ii.
All that seems to be changing. As well as the R5 (an obvious A7s3 competitor for the combined video/stills market), there's also talk of a 75MP body/sensor with a focus on DR - an obvious competitor to the A7r4.
I doubt Canon is ready to take on Sony's AF system for fast action yet. If it was, we would certainly have seen signs of a 400/2.8 or other fast supertele coming in time for the Tokyo Olympics - Canon already has the optical designs for these, so altering the mechanics and fitting the optics into a new lens suitable for mirrorless cameras would be relatively quick, if there were a current need for them. But it appears that they're ready to take on the A7/r/s series. Even if their AF system isn't quite there yet, that isn't so critical when competing against the A7s3 (since video is less AF-dependent than stills) or the A7r4 (since it is most frequently used in high-resolution, non-action roles, despite its AF system being more than action-capable). What this tells us is that they're making rapid progress and are taking mirrorless seriously.
I'd expect an A9 (probably A9iii) competitor in time for the 2022 soccer world cup, with a 400/2.8, and possibly other superteles, ready for the same event.
All of which suits me perfectly well. By 2024-2025, Canon should have a mature (if not fully comprehensive) mirrorless lens and body lineup, with all bases covered (action body, hi-res body, general-purpose body, entry-level body, UWA, f/2.8 zooms, f/4 zooms, fast primes, macro, superteles, lightweight long tele zoom) and a few oddball/niche lenses. By that stage, most of my Sony gear will have done its money's worth and be ripe for replacement, with second-generation (or even third-generation) versions of the 24-70/2.8, 70-200/2.8, 100-400/4.5-5.6 and other core lenses released (and the initial versions with little value left and ripe for replacement), with the A7r4 and A9 reaching the end of service life and new bodies likely boasting technologies such as global shutters. It will be good to have two equally-viable, equally-comprehensive systems to choose from at that stage, with a good market for used lenses to dispose of old gear at a fair price, and the choice of system coming down to things like the relative strengths and weaknesses of individual lenses and bodies (rather like the Canon/Nikon competition in SLRs), rather than the current situation of having no other viable system if you need a future-proofed mirrorless system with a comprehensive lens and body lineup capable of shooting anything. (Superteles likely won't need replacement, but it's easy to run a dedicated wildlife setup on a completely different system to your general photography kit, since they don't share many common components anyway - I ran a Canon action/wildlife setup alongside a Sony general kit for years).
Regarding the new lenses, I'm unsure about the 100-500 f/4.5-7.1. Depending on the details, it could be anything from an even-better 100-400L or consumer-grade rubbish. Is it basically a 100-400/4.5-5.6, similar in optics and construction, which can extend a bit further, to 500/7.1? Or is it more like a cheap Sigma/Tamron supertele zoom, designed to get reach while being budget-friendly? Most importantly, where is the transition point from f/5.6 to f/6.3 or f/7.1? If it's 400mm, it could be an even better 100-400L - the current Sony version is probably the most useful telephoto lens out there for the landscape/travel photographer, covering all your telephoto needs for landscape photography while being able to shoot the occasional wildlife shot in a pinch (great for a trip not entirely dedicated to wildlife with large lenses) and extending it to 500mm would make it even more versatile, provided there isn't an optical quality or aperture compromise (at the same focal length). I'm hoping it's the former - there are enough budget superteles out there that Canon doesn't need to bring one out too, and Canon is never going to compete with Sigma and Tamron on price.
45mp full-frame CMOS sensor all we know is at least 33MP, due to 8K
If they maintain the 3:2 aspect ratio, it will have to be at least 39MP, if using 7680x4320 as '8k'. For 'true' 8k (8192x4608), they'd need 45MP.
For 7680px on the long side, you'd need 7680x5120, or 39MP, for a 3:2 aspect ratio.
For 8192px on the long side, you'd need 8192x5462, or 45MP, for a 3:2 aspect ratio.
If they go for 33MP and a 16:9 aspect ratio, what they have is a video camera that can take stills, not a stills camera.
