Both Nikon S9900 and Nikon D4s have 16.0 MP resolution sensors but Nikon S9900's sensor is 1/2.3' (6.17 x 4.55 mm ) and Nikon D4s's sensor is Full frame (36 x 23.9 mm ).
Since Nikon D4s's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Nikon S9900.
Below you can see the S9900 and D4s sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon S9900 and Nikon D4s Cameras
As seen above, Nikon D4s has a 30.7x Larger sensor area than Nikon S9900. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in 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 S9900
or the
Nikon D4s ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3' versus Full frame),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
