Canon 300D has a
6.0MP APS-C (22.7 x 15.1 mm ) sized CMOS sensor . On the other hand, Canon 1D X III has a
20.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Digic X processor.
Canon 1D X III's sensor provides 14MP more than Canon 300D's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the 300D and 1D X MIII sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 300D and Canon 1D X III Cameras
As seen above, Canon 1D X III has a 2.5x Larger sensor area than Canon 300D. 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 300D and Canon 1D X III sensors have been tested by DxO and the results show that 1D X MIII has a better overall score of 91, 36 points higher compared to 300D's score of 55.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 300D
55
21.0 bits
10.8 Evs
544 ISO
Canon 1D X III
91
24.2 bits
14.5 Evs
3248 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 300D
or the
Canon 1D X III ,
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.
