Sony H50 has a
9.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Sony H20 has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the H50 and H20 sensor size comparison.
Sony H50 and Sony H20 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 H50 has 11% larger pixel area compared to Sony H20, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.