Dual Pixel CMOS AF is an autofocus technology developed by Canon that aims to deliver the speed and responsiveness of phase detection autofocus using only the camera sensor and not a separate phase detection sensor. This has many advantages for mirrorless cameras and DSLRs being used in live view mode. Effectively, the photosites on Canon’s sensor are split into two, and the two ‘halves’ can be used to measure the distance of the subject by how much the two halves are ‘out of phase’. Other makers have their own on-sensor phase-detection autofocus systems. It erodes one of the few remaining advantages of DSLR cameras over mirrorless models.