Both Nikon 1 J5 and Nikon Z50 have 21.0 MP resolution sensors but Nikon 1 J5's sensor is 1' (13.2 x 8.8 mm ) and Nikon Z50's sensor is APS-C (23.5 x 15.7 mm ).
Since Nikon Z50'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 1 J5.
Another similarity between these two cameras is that both Nikon Z50 and Nikon 1 J5 sensors lack anti-alias (Low-Pass) filters. 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 J5 and Z50 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon 1 J5 and Nikon Z50 Cameras
As seen above, Nikon Z50 has a 3.2x Larger sensor area than Nikon 1 J5. 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 1 J5
or the
Nikon Z50 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1' versus APS-C),
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.