Both Nikon S6500 and Panasonic GH4 have 16.0 MP resolution sensors but Nikon S6500's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Panasonic GH4's sensor is Four Thirds (17.3 x 13 mm ).
Since Panasonic GH4'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 S6500.
Below you can see the S6500 and GH4 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon S6500 and Panasonic GH4 Cameras
As seen above, Panasonic GH4 has a 8.0x Larger sensor area than Nikon S6500. 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 S6500
or the
Panasonic GH4 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch versus Four Thirds),
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.
