Both Nikon D5100 and Nikon D7000 have APS-C sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the D5100 and D7000 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D5100 and Nikon D7000 Cameras
Nikon D5100 and Nikon D7000 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
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
Nikon D5100
80
23.5 bits
13.6 Evs
1183 ISO
Nikon D7000
80
23.5 bits
13.9 Evs
1167 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 D5100
or the
Nikon D7000 ,
including hyperfocal distance.
