Both Nikon D1H and Sigma SD10 have APS-C sized 3.0 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 Sigma SD10'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 D1H and SD10 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D1H and Sigma SD10 Cameras
As seen above, Nikon D1H has a 1.3x Larger sensor area than Sigma SD10. 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.
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
Nikon D1H
or the
Sigma SD10 ,
including hyperfocal distance.
