Both Sony RX1R and Ricoh GR IIIx HDF have 24.0 MP resolution sensors but Sony RX1R's sensor is Full frame (35.8 x 23.9 mm ) and Ricoh GR IIIx HDF's sensor is APS-C (23.5 x 15.6 mm ).
Since Sony RX1R'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 Ricoh GR IIIx HDF.
Another similarity between these two cameras is that both Ricoh GR IIIx HDF and Sony RX1R 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 RX1R and GR IIIx HDF sensor size comparison.
Sensor Size and Resolution Comparison image of Sony RX1R and Ricoh GR IIIx HDF Cameras
As seen above, Sony RX1R has a 2.3x Larger sensor area than Ricoh GR IIIx HDF. 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
Sony RX1R
or the
Ricoh GR IIIx HDF ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame 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.
