Panasonic TS3 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine FHD processor. On the other hand, Panasonic TS20 has a
16.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the TS3 and TS20 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic TS3 and Panasonic TS20 Cameras
Panasonic TS3 and Panasonic TS20 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 Panasonic TS3 has 32% larger pixel area compared to Panasonic TS20, 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
Panasonic TS3
or the
Panasonic TS20 ,
including hyperfocal distance.