Defraction limit using a digital camera
Due to the diffraction limit the diameter of a pixel is d = 2.44 · ? · B, where F-number B and the wavelength ? determined. With a typical value of ? = 555nm we obtain d = B · 1.3?m. The typical pixel size of today's digital SLR cameras is about 5?m, so that we reached at f / 4, the theoretical limit. Digital Cameras have in some cases significantly smaller pixel sizes because they work with smaller image sensors.