Both Sony A450 and Sony A390 have APS-C sized 14.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the A450 and A390 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A450 and Sony A390 Cameras
Sony A450 and Sony A390 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
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A450
66
21.8 bits
11.8 Evs
769 ISO
Sony A390
66
22.5 bits
11.5 Evs
607 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 A450
or the
Sony A390 ,
including hyperfocal distance.
