Both Sony RX100 III and Sony RX100 II have 20.0 MP resolution sensors but Sony RX100 III's sensor is 1″ (13.2 x 8.8 mm ) and Sony RX100 II's sensor is 1-inch (13.2 x 8.8 mm ).
Since Sony RX100 II'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 Sony RX100 III.
Below you can see the RX100 III and RX100 II sensor size comparison.
Sensor Size and Resolution Comparison image of Sony RX100 III and Sony RX100 II Cameras
Sony RX100 III and Sony RX100 II 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
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony RX100 III
67
22.4 bits
12.3 Evs
495 ISO
Sony RX100 II
67
22.5 bits
12.4 Evs
483 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
Sony RX100 III
or the
Sony RX100 II ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1″ versus 1-inch),
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.
