Kodak M550 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Kodak FZ55 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor .
Below you can see the M550 and FZ55 sensor size comparison.
Sensor Size and Resolution Comparison image of Kodak M550 and Kodak FZ55 Cameras
Kodak M550 and Kodak FZ55 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 Kodak M550 has 32% larger pixel area compared to Kodak FZ55, 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
Kodak M550
or the
Kodak FZ55 ,
including hyperfocal distance.