Both Sony RX100 IV and Sony RX100 III have 1″ sized 20.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the RX100 IV and RX100 III sensor size comparison.
Sensor Size and Resolution Comparison image of Sony RX100 IV and Sony RX100 III Cameras
Sony RX100 IV and Sony RX100 III 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
Both Sony RX100 IV and Sony RX100 III sensors have been tested by DxoMark. DxoMark 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. Of the two cameras that we are comparing, RX100 IV has scored 70, 3 points higher than RX100 III.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony RX100 IV
70
22.9 bits
12.6 Evs
562 ISO
Sony RX100 III
67
22.4 bits
12.3 Evs
495 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 IV
or the
Sony RX100 III ,
including hyperfocal distance.
