Olympus 7040 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor. On the other hand, Leica V-Lux 3 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor .
Below you can see the 7040 and V-Lux 3 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus 7040 and Leica V-Lux 3 Cameras
Olympus 7040 and Leica V-Lux 3 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
Olympus 7040
or the
Leica V-Lux 3 ,
including hyperfocal distance.