Sony RX100 IV has a
20.0MP 1″ (13.2 x 8.8 mm ) sized Stacked BSI-CMOS sensor and features Bionz X processor. On the other hand, Sony RX1R has a
24.0MP Full frame (35.8 x 23.9 mm ) sized CMOS sensor .
One other difference between these two cameras that is worth mentioning is that Sony RX1R's sensor doesn't have an anti-alias (Low-Pass) filter. 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 RX100 IV and RX1R sensor size comparison.
Sensor Size and Resolution Comparison image of Sony RX100 IV and Sony RX1R Cameras
As seen above, Sony RX1R has a 7.4x Larger sensor area than Sony RX100 IV. 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.
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. Sony RX100 IV and Sony RX1R sensors have been tested by DxO and the results show that RX1R has a better overall score of 91, 21 points higher compared to RX100 IV's score of 70.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony RX100 IV
70
22.9 bits
12.6 Evs
562 ISO
Sony RX1R
91
25.0 bits
13.6 Evs
2537 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 RX1R ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1″ versus Full frame),
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.