Both Panasonic G1 and Panasonic GH1 have Four Thirds sized 12.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the G1 and GH1 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic G1 and Panasonic GH1 Cameras
As seen above, Panasonic GH1 has a 1.2x Larger sensor area than Panasonic G1. 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. Panasonic G1 and Panasonic GH1 sensors have been tested by DxO and the results show that GH1 has a better overall score of 64, 11 points higher compared to G1's score of 53.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Panasonic G1
53
21.1 bits
10.3 Evs
463 ISO
Panasonic GH1
64
21.6 bits
11.6 Evs
772 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 G1
or the
Panasonic GH1 ,
including hyperfocal distance.
