Nikon L820 has a
16.0MP 1/2.3-inch (6.16 x 4.62 mm ) sized BSI-CMOS sensor . On the other hand, Panasonic ZS80 has a
20.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features Venus Engine processor.
Below you can see the L820 and ZS80 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon L820 and Panasonic ZS80 Cameras
Nikon L820 and Panasonic ZS80 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the 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
Nikon L820
or the
Panasonic ZS80 ,
including hyperfocal distance.