Canon SX40 HS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Panasonic FZ40 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine HD II processor.
Below you can see the SX40 HS and FZ40 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon SX40 HS and Panasonic FZ40 Cameras
Canon SX40 HS and Panasonic FZ40 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.
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
Canon SX40 HS
or the
Panasonic FZ40 ,
including hyperfocal distance.