Panasonic ZS7 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine HD II processor. On the other hand, Canon A800 has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features DIGIC 3 processor.
Below you can see the ZS7 and A800 sensor size comparison.
Panasonic ZS7 and Canon A800 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.