Both Nikon D5500 and Sony A65 have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another difference between these two cameras is that Nikon D5500's sensor lacks 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 D5500 and A65 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D5500 and Sony A65 Cameras
Nikon D5500 and Sony A65 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
Both Nikon D5500 and Sony A65 sensors have been tested by DxoMark. DxoMark 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. Of the two cameras that we are comparing, D5500 has scored 84, 10 points higher than A65.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D5500
84
24.1 bits
14.0 Evs
1438 ISO
Sony A65
74
23.4 bits
12.6 Evs
717 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 D5500
or the
Sony A65 ,
including hyperfocal distance.
