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, Nikon D810 has a
36.0MP Full frame (35.9 x 24 mm ) sized CMOS sensor and features EXPEED 4 processor.
Nikon D810's sensor provides 24MP 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.
One other difference between these two cameras that is worth mentioning is that Nikon D810'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 D300S and D810 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D300S and Nikon D810 Cameras
As seen above, Nikon D810 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 Nikon D810 sensors have been tested by DxO and the results show that D810 has a better overall score of 97, 27 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
Nikon D810
97
25.7 bits
14.8 Evs
2853 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
Nikon D810 ,
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.
