Both Nikon D70s and Nikon D50 have APS-C sized 6.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the D70s and D50 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D70s and Nikon D50 Cameras
Nikon D70s and Nikon D50 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
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. Nikon D70s and Nikon D50 sensors have been tested by DxO and the results show that D50 has a better overall score of 55, 5 points higher compared to D70s's score of 50.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D70s
50
20.4 bits
10.3 Evs
529 ISO
Nikon D50
55
20.9 bits
10.8 Evs
560 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
Nikon D70s
or the
Nikon D50 ,
including hyperfocal distance.
