The D5100 utilizes a 16.2 megapixel DX format CMOS sensor to capture images.

This sensor has the same specs of the sensor used by the Nikon D7000.

Chipworks reports that each pixel is 4.8 µm wide. That's about half the diameter of a red blood cell!

The sensor has a special glass cover that turns red when viewed at an angle. Neat! (This is the "hot mirror," which filters out the infrared spectrum.)