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, Sony T99 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Bionz processor.
Below you can see the TX20 and T99 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony TX20 and Sony T99 Cameras
Sony TX20 and Sony T99 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 Sony T99 has 14% larger pixel area (2.01µm 2 vs 1.76µm 2 ) compared to Sony TX20, it has larger pixel area to collect light hence potential to 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
Sony TX20
or the
Sony T99 ,
including hyperfocal distance.