Sony TX20 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features BIONZ processor. On the other hand, Olympus VH-515 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features TruePic III+ processor.
Below you can see the TX20 and VH-515 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony TX20 and Olympus VH-515 Cameras
Sony TX20 and Olympus VH-515 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
Sony TX20
or the
Olympus VH-515 ,
including hyperfocal distance.