Both Sony A9 II and Sony A9 have Full frame sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the A9 Mark II and A9 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A9 II and Sony A9 Cameras
Sony A9 II and Sony A9 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 A9 II and Sony A9 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, A9 Mark II has scored 93, 1 points higher than A9.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A9 II
93
25.0 bits
14.0 Evs
3434 ISO
Sony A9
92
24.9 bits
13.3 Evs
3517 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 A9 II
or the
Sony A9 ,
including hyperfocal distance.
