Nikon S640 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Expeed processor. On the other hand, Sony TX5 has a
10.0MP 1/2.4-inch (6.104 x 4.578 mm ) sized BSI-CMOS sensor and features Bionz processor.
Below you can see the S640 and TX5 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon S640 and Sony TX5 Cameras
Nikon S640 and Sony TX5 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the 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 S640
or the
Sony TX5 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch versus 1/2.4-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.