Nikon D800 has a
36.0MP Full frame (35.9 x 24 mm ) sized CMOS sensor and features Expeed 3 processor. On the other hand, Sony A7 V has a
33.0MP Full frame (35.8 x 23.8 mm ) sized Partially-Stacked CMOS sensor and features Bionz XR2 processor.
One other difference between these two cameras that is worth mentioning is that Sony A7 V's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the D800 and A7 V sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D800 and Sony A7 V Cameras
Nikon D800 and Sony A7 V have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Nikon D800
or the
Sony A7 V ,
including hyperfocal distance.
