I don't care about having 10 or 12 fps, that's what the 1dx is for, if I want fast shooting I'll use my 7d Mk 2
I don't care as well for high resolution camera, if the quality, DR, noise, is the same as the 7d2 (which is ok but not impressive at all).
This is why I will skip the 5ds /5dsr.
What I care for, and the reason I chose 6d over 5d3 was the better image quality AND the capability of the AF to focus at -3 EV (instead of -2EV for 5d3)
I shoot a lot of evening and night parties, and portrait with ambiant light (or whatever light I have), and my 85mm f1.2L II @ f1.2 is my secret weapon for that. I cursed the 5d2 for that, being a camera that I used a lot, i did not understand why canon underestimated the need for technology improvements in AF technology for so long. That's how i became skilled in the "switch to live view + zoom + manual focus + shoot" when the AF was unable to catch anything (which happened a lot, given the -0.5 EV AF sensitivity of 5d2)
I find the AF points of 7d2 too thick and wide, difficult to get a very precise focus with my f1.2 lenses. The 6d center point is much more precise in this area.
What is the need for super high iso or image quality if you cant focus at all...?
What I want in the 5D4, what would really make me buy it would be :
A new AF module :
-3EV able AF (or -4EV !), all cross points, ideally all compatible to f8 lenses (maybe more?) no need for 65 AF points, 20 or so is Ok if all of them are cross type, and more than one is double cross type.
I don't want to see any differences between 1600 isos and 6400 isos (the really usable max iso setting is 3200 of the 6d, and a little less of the 5d3, like 2500). Acceptable quality for portraits, or high quality printing, or fashion.
I want clean 12800 isos, clean enough to make something of the pictures (like downsized printing).
Dual card CF / SD UHS II
Antiflicker technology like on the 7d2 (great idea)
A really improved sensor with more DR (at least 1 stop more). If Canon would make a technology partnership with sony to leap for their old sensor tech, to exmor like BSI design, they would be king of the hill.
24 to 30 Mp not more
5 to 8 fps is enough
heavily tropicalized body.
What would be "nice to have"
50 to 120 fps 1080p video shooting
on sensor AF points like on the 7d2 and latest rebels, for continuous AF in movie mode.
different Movie AF algorythms (like the power focus feature on long telephotos lenses), quick, progessive, ...
Wifi/GPS (GPS is nice when traveling), I never used wifi for my 6d yet.
I don't care about 4k vids yet, but a 4k mode at 24 or 30fps would be nice for marketing purpose. 5d serie has a tradition of breaking through (first affordable FF body, First FF body that shoots video,...) The 5d3 brought nothing really new (that says a lot about canon lagging on one of the core tech of photography today : sensors...). If Canon keeps playing solo for sensor tech and/or bring nothing new that the same technology for their next sensor, they will have to include 4k for marketing.
And of course, I would like bold decisions for lenses (like the come back of f1.0 lenses!).
Too much dreaming i gess...
