Both Sony A700 and Nikon D300S have APS-C sized 12.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the A700 and D300S sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A700 and Nikon D300S Cameras
Sony A700 and Nikon D300S have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the 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. Sony A700 and Nikon D300S sensors have been tested by DxO and the results show that D300S has a better overall score of 70, 4 points higher compared to A700's score of 66.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A700
66
22.3 bits
11.9 Evs
581 ISO
Nikon D300S
70
22.5 bits
12.2 Evs
787 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 A700
or the
Nikon D300S ,
including hyperfocal distance.
