Both Nikon P340 and Canon S120 have 1/1.7-inch sized 12.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the P340 and S120 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon P340 and Canon S120 Cameras
Nikon P340 and Canon S120 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Nikon P340 and Canon S120 sensors have been tested by DxO and the results show that S120 has a better overall score of 56, 2 points higher compared to P340's score of 54.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon P340
54
20.7 bits
11.9 Evs
273 ISO
Canon S120
56
21.3 bits
11.9 Evs
246 ISO
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 P340
or the
Canon S120 ,
including hyperfocal distance.
