Pentax K-S1 has a
20.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Prime MII processor. On the other hand, Samsung GX-20 has a
15.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor .
Pentax K-S1's sensor provides 5MP more than Samsung GX-20'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.
Another difference between these two cameras is that Pentax K-S1's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the K-S1 and GX-20 sensor size comparison.
Pentax K-S1 and Samsung GX-20 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.
DxOMark Sensor Scores
Both Pentax K-S1 and Samsung GX-20 sensors have been tested by DxoMark. DxoMark scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Of the two cameras that we are comparing, K-S1 has scored 78, 10 points higher than GX-20.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Pentax K-S1 |
78 |
23.5 bits |
13.0 Evs |
1061 ISO |
Samsung GX-20 |
68 |
23.1 bits |
11.2 Evs |
714 ISO |