Sony HX100V 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, Panasonic FZ200 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Venus Engine VII FHD processor.
Below you can see the HX100V and FZ200 sensor size comparison.
Sony HX100V and Panasonic FZ200 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 FZ200 has 32% larger pixel area (2.34µm2 vs 1.76µm2) compared to Sony HX100V, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.