Nikon P7700 has a
12.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized CMOS sensor . On the other hand, Pentax K-m has a
10.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor .
Below you can see the P7700 and K-m sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon P7700 and Pentax K-m Cameras
As seen above, Pentax K-m has a 8.9x Larger sensor area than Nikon P7700. 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 P7700 and Pentax K-m sensors have been tested by DxO and the results show that K-m has a better overall score of 64, 11 points higher compared to P7700's score of 53.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon P7700
53
21.1 bits
11.7 Evs
191 ISO
Pentax K-m
64
22.4 bits
11.4 Evs
513 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 P7700
or the
Pentax K-m ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/1.7-inch versus APS-C),
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.
