Pentax RZ18 has a
16.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Olympus 7040 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor.
Below you can see the RZ18 and 7040 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax RZ18 and Olympus 7040 Cameras
Pentax RZ18 and Olympus 7040 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 7040 has 15% larger pixel area (2.01µm 2 vs 1.74µm 2 ) compared to Pentax RZ18, it has larger pixel area to collect light hence potential to 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
Pentax RZ18
or the
Olympus 7040 ,
including hyperfocal distance.
