Canon 7D has a
18.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features Dual Digic 4 processor. On the other hand, Canon 1Ds MIII has a
21.0MP Full frame (36 x 24 mm ) sized CMOS sensor .
Below you can see the 7D and 1Ds MIII sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 7D and Canon 1Ds MIII Cameras
As seen above, Canon 1Ds MIII has a 2.6x Larger sensor area than Canon 7D. 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 7D and Canon 1Ds MIII sensors have been tested by DxO and the results show that 1Ds MIII has a better overall score of 80, 14 points higher compared to 7D's score of 66.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 7D
66
22.0 bits
11.7 Evs
854 ISO
Canon 1Ds MIII
80
24.0 bits
12.0 Evs
1663 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 7D
or the
Canon 1Ds MIII ,
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.
