Both Nikon D80 and Canon A495 have 10.0 MP resolution sensors but Nikon D80's sensor is APS-C (23.6 x 15.8 mm ) and Canon A495's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Nikon D80's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Canon A495.
Below you can see the D80 and A495 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D80 and Canon A495 Cameras
As seen above, Nikon D80 has a 13.3x Larger sensor area than Canon A495. 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.