Kodak M320 has a
9.0MP 1/2.5-inch (5.744 x 4.308 mm ) sized CCD sensor . On the other hand, Kodak M381 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the M320 and M381 sensor size comparison.
As seen above, Kodak M381 has a 1.1x Larger sensor area than Kodak M320. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.