Both Panasonic GH4 and Panasonic GX85 have Four Thirds sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
One other difference between these two cameras that is worth mentioning is that Panasonic GX85'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 GH4 and GX85 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic GH4 and Panasonic GX85 Cameras
Panasonic GH4 and Panasonic GX85 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 Panasonic GH4 and Panasonic GX85 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, GH4 has scored 74, 3 points higher than GX85.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Panasonic GH4
74
23.2 bits
12.8 Evs
791 ISO
Panasonic GX85
71
22.9 bits
12.6 Evs
662 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
Panasonic GH4
or the
Panasonic GX85 ,
including hyperfocal distance.
