Sensor size- The sensor of a camera is combination of many pixels or photo site’s, which main function is to receive the light photon coming through the lenses and then it sends the signal for processing the image of the scene. Usually, a smartphone cameras sensor size is smaller than a DSLR, SLR. Camera’s sensor size is one of the most important to get a best quality image. Bigger the sensor size better image quality. Along with the size of sensor the size of pixel or photocells it has also affected the quality.

      If the sensor with increased number of pixel or photo sites then the photo sites size gets reduced and hence the pixel can capture not enough light. So, the image quality is not good enough.

      This same situation occurs in smartphone because the smart phone has a small sensor but when its megapixel number is increased resolution of the image can increase but the photo quality may not good.