Canon 70D has a
20.0MP APS-C (22.5 x 15 mm ) sized CMOS sensor and features Digic 5+ processor. On the other hand, Canon 5D MII has a
21.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Digic 4 processor.
Below you can see the 70D and 5D MII sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 70D and Canon 5D MII Cameras
As seen above, Canon 5D MII has a 2.6x Larger sensor area than Canon 70D. 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 70D and Canon 5D MII sensors have been tested by DxO and the results show that 5D MII has a better overall score of 79, 11 points higher compared to 70D's score of 68.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 70D
68
22.5 bits
11.6 Evs
926 ISO
Canon 5D MII
79
23.7 bits
11.9 Evs
1815 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 70D
or the
Canon 5D MII ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(APS-C versus Full frame),
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.
