Panasonic FX48 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Panasonic LZ20 has a
16.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the FX48 and LZ20 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic FX48 and Panasonic LZ20 Cameras
Panasonic FX48 and Panasonic LZ20 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 FX48 has 32% larger pixel area compared to Panasonic LZ20, 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 FX48
or the
Panasonic LZ20 ,
including hyperfocal distance.