Canon SX170 IS has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor. On the other hand, Nikon P7800 has a
12.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized BSI-CMOS sensor .
Below you can see the SX170 IS and P7800 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon SX170 IS and Nikon P7800 Cameras
As seen above, Nikon P7800 has a 1.5x Larger sensor area than Canon SX170 IS. 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.
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 SX170 IS
or the
Nikon P7800 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch versus 1/1.7-inch),
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.