Sony a5100 has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz X processor. On the other hand, Samsung NX5 has a
15.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor and features DRIM Engine processor.
Sony a5100's sensor provides 9MP more than Samsung NX5'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 a5100 and NX5 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony a5100 and Samsung NX5 Cameras
Sony a5100 and Samsung NX5 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
Sony a5100
or the
Samsung NX5 ,
including hyperfocal distance.