Both Pentax WG-2 GPS and Ricoh WG-4 GPS have 1/2.3-inch sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the WG-2 GPS and WG-4 GPS sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax WG-2 GPS and Ricoh WG-4 GPS Cameras
Pentax WG-2 GPS and Ricoh WG-4 GPS 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 Pentax WG-2 GPS has 15% larger pixel area compared to Ricoh WG-4 GPS, 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
Pentax WG-2 GPS
or the
Ricoh WG-4 GPS ,
including hyperfocal distance.
