Nikon D300S has a
12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor and features Expeed processor. On the other hand, Canon 6D MII has a
26.0MP Full frame (35.9 x 24 mm ) sized CMOS sensor and features DIGIC 7 processor.
Canon 6D MII's sensor provides 14MP more than Nikon D300S'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 D300S and 6D MII sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D300S and Canon 6D MII Cameras
As seen above, Canon 6D MII has a 2.3x Larger sensor area than Nikon D300S. 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. Nikon D300S and Canon 6D MII sensors have been tested by DxO and the results show that 6D MII has a better overall score of 85, 15 points higher compared to D300S's score of 70.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D300S
70
22.5 bits
12.2 Evs
787 ISO
Canon 6D MII
85
24.4 bits
11.9 Evs
2862 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 D300S
or the
Canon 6D 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.