Both Ricoh GR and Nikon A have APS-C sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the GR and A sensor size comparison.
Sensor Size and Resolution Comparison image of Ricoh GR and Nikon A Cameras
Ricoh GR and Nikon A 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.
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. Ricoh GR and Nikon A sensors have been tested by DxO and the results show that A has a better overall score of 80, 2 points higher compared to GR's score of 78.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Ricoh GR
78
23.6 bits
13.5 Evs
972 ISO
Nikon A
80
23.4 bits
13.8 Evs
1164 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
Ricoh GR
or the
Nikon A ,
including hyperfocal distance.
