Canon 5D MII has a
21.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Digic 4 processor. On the other hand, Nikon D7100 has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor .
One other difference between these two cameras that is worth mentioning is that Nikon D7100's sensor doesn't have an 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 5D MII and D7100 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 5D MII and Nikon D7100 Cameras
As seen above, Canon 5D MII has a 2.4x Larger sensor area than Nikon D7100. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in 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. Canon 5D MII and Nikon D7100 sensors have been tested by DxO and the results show that D7100 has a better overall score of 83, 4 points higher compared to 5D MII's score of 79.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 5D MII
79
23.7 bits
11.9 Evs
1815 ISO
Nikon D7100
83
24.2 bits
13.7 Evs
1256 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
Canon 5D MII
or the
Nikon D7100 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame versus APS-C),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
