D800E to 5d mk. III? paralyzed by analysis

In a way thats quite situation dependent. Using both side by side for the D800 outresolves its counterpart by about half of a stop. Strange metric? Sure, but I use both outdoors & at max sync speed stopped down to f/16, give or take. Reduced flash power is nice too.

And on the other end of the illumination spectrum lenses make the sensor a secondary factor.