Leica TL has a
16.0MP APS-C (23.6 x 15.7 mm ) sized CMOS sensor . On the other hand, Pentax K10D has a
10.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor .
Leica TL's sensor provides 6MP more than Pentax K10D's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the TL and K10D sensor size comparison.
Sensor Size and Resolution Comparison image of Leica TL and Pentax K10D Cameras
Leica TL and Pentax K10D 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
Leica TL
or the
Pentax K10D ,
including hyperfocal distance.