More information- 30.3MP sensor. Despite the similar resolution, it has to be a completely different design to the 5D4 sensor, in order to incorporate dual pixel AF. If it even matches it in image quality, it will be more than a credible sensor given its product placement, but, given that the 5D4 is two years old, there's a reasonable chance the new sensor will outperform it.
- AF to EV -6. This is a big one - neither Nikon's nor Sony's current offerings (whether SLR or mirrorless) can match this. Of course, being
technically able to focus in such darkness is different from actually being competent and reliable when doing so - if you can even see what you're trying to focus on in the first place.
- AF coverage - 100% vertical, 88% horizontal. Meh - unless you're tracking wildlife, since when did you need to focus on things at the edge of the frame? Even when tracking wildlife, you'd probably be acquiring focus somewhere around the middle third of the frame anyway. AF near the edge is mostly to continue tracking the subject as it moves within the frame, not to actually shoot with. And we probably won't have long, fast superteles for action/wildlife photography for a while anyway - not within the product cycle of this first-generation body (except see last point).
- 4K video. Good, but is this at 60fps or 25/30fps? And what's the output format?
- Same battery as the 5D series, so lots of power available.
- 580g weight. No indication of whether this is with or without the battery. Either way, it's tiny.
- 54x20mm lens mount. This would clash with an EF mount, so the mount won't be able to take both EF and RF lenses.
- The adapter mentioned is an EF-to-R adapter. So definitely no dual-capable mount, otherwise they wouldn't need it. There was mention of a 'control ring adapter' and a 'drop-in filter adapter' - no idea if they're the same thing. [EDIT: Looks like they're three different adapters]
Re: long telephotos:
- No RF-mount long telephotos likely in the immediate future, but the 400/2.8 III and 600/4 III are due to be announced at around the same time. If these use linear stepper motors instead of Canon's ring USM system, they should be usable on mirrorless bodies with no loss of AF capability (this goes with both Canon and Sony bodies, via a Metabones adapter). Most older lenses, obviously, will not have these motors and will suffer a loss of performance. Really, with mirrorless and video taking off and adapters playing a significant role, there is little reason for Canon, Nikon and Sigma to design any future lenses without linear stepper motors, for dual use on mirrorless and SLR bodies.