A complementary metal oxide semiconductor field effect transistor (CMOS-FET) image sensor. An active photosensing pixel is formed on a substrate. At least one side of the pixel has a width equal to or less than approximately 3 μm. At least one dielectric layer is disposed on the substrate covering the pixel. A color filter is disposed on the least one dielectric layer. A microlens array is disposed on the color filter of the pixel, and the sum of the thickness of all dielectric layers and the color filter divided by the pixel width is equal to or less than approximately 1.87.