Both Nikon A1000 and Sony TX20 have 16.0 MP resolution sensors but Nikon A1000's sensor is 1/2.3 (6.17 x 4.55 mm ) and Sony TX20's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Sony TX20'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 Nikon A1000.
Below you can see the A1000 and TX20 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon A1000 and Sony TX20 Cameras
Nikon A1000 and Sony TX20 have the same sensor sizes so they will provide same level of control over the depth of field when used with 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
Nikon A1000
or the
Sony TX20 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3 versus 1/2.3-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.
