Olympus VR-320 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features TruePic III processor. On the other hand, Panasonic ZS40 has a
18.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Venus Engine processor.
Below you can see the VR-320 and ZS40 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus VR-320 and Panasonic ZS40 Cameras
Olympus VR-320 and Panasonic ZS40 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 Olympus VR-320 has 30% larger pixel area compared to Panasonic ZS40, 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
Olympus VR-320
or the
Panasonic ZS40 ,
including hyperfocal distance.