Sony H55 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Bionz processor. On the other hand, Sony HX5 has a
10.0MP 1/2.4-inch (6.104 x 4.578 mm ) sized BSI-CMOS sensor and features Bionz processor.
Below you can see the H55 and HX5 sensor size comparison.
Sony H55 and Sony HX5 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.