keep in mind that the 6d shots are softer
What? Where did you get that from?
I've never shot a 5D3 but the 6D shots are just as sharp as my 5D2 shots... why would there be a difference in sharpness between any of the full frame sensors?
actually the 5D MK2 has the highest spatial resolution of the three cameras.
a lot of reviews confirm this.
but you have to shoot testcharts to see it or pixelpeep pictures of the same motive to notice it.
yet it IS visible.
the reason is a marginal lower MP number of the 6D (but that is really marginal) another reason is the difference in the AA filter.
i guess the 6D has a stronger AA filter then the other two cameras.
if that´s the case it is a shame that there is so much moire in 6D videos.
anyway, not all FF sensors are equal...
Im kind of a pixel peeper myself, but almost by accident. I am viewing my shots at 24" on a 1920x1200 monitor, and judging them. My wife wanted a 8.5x11 print of a tiger lilly I shot last summer, and on my PC I thought, ehh, its not real sharp but W/E and had a print of it made. at 8.5x11 in our hallway it looks super-sharp, and gets alot of comments. Maybe a 2' print in a restaurant on a wall, 1' from someones face it may look soft. SOOO many amazing shots have come from 12 MP 5d classics, and alot even cropped. Just a little point on pixel peeping I guess, Rant over haha