Canon SD4000 IS has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features Digic 4 processor. On the other hand, Sony TX20 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features BIONZ processor.
Sony TX20's sensor provides 6MP more than Canon SD4000 IS's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the SD4000 IS and TX20 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon SD4000 IS and Sony TX20 Cameras
Canon SD4000 IS 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. On the other hand, since Canon SD4000 IS has 59% larger pixel area compared to Sony TX20, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.
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 SD4000 IS
or the
Sony TX20 ,
including hyperfocal distance.
