Samsung NX500 has a 28.0MP APS-C (23.5 x 15.7 mm ) sized BSI-CMOS sensor and features DRIMe 5 processor. You can shoot at maximum resolution of 6480 x 4320 pixels with aspect ratios of 1:1, 3:2 and 16:9. NX500 has a native ISO range of 100 - 25600 which can be boosted to 51200 and it can save files in RAW format which gives you a wider room for post processing.
Samsung NX500 is not the highest resolution APS-C camera. Canon M6 MII with its 33.0MP sensor is leading in this class. Check the comparison of Samsung NX500 vs Canon M6 MII or take a look at Highest resolution Mirrorless cameras list.
Samsung NX500 DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. Samsung NX500 sensor has been tested by DxO Mark and got an overall score of 87 for its image quality. You can find the details of their analysis of Samsung NX500 here.
Another important feature about Samsung NX500's sensor is the lack of anti-alias (Low-pass) filter. Removing anti-aliasing filter increases the sharpness and level of detail but on the other side it also increases the chance of moire occurring in certain scenes.
Let's look at how the size of the Samsung NX500's APS-C sensor compares with other standard sensor sizes.