>>3343137Vaguely similar. You're still lensing the light to a left and right side. See:
https://www.dpreview.com/articles/2151234617/fujifilmpd And an interesting tidbit:
> In the above paragraph I specifically mentioned DSLR PDAF. There is also on-sensor PDAF in some DSLRs (for use during video), and in some mirrorless cameras. PDAF works by measuring independently the light from each side of the lens, so PDAF only works when the PDAF sensors can see each side of the lens, and that can be done only when the PDAF sensors are intercepting the light cone from the lens away from actual focus. When the subject is in focus with on-sensor PDAF, light from both sides of the lens is mixed in the circle of confusion near focus. Thus, on-sensor PDAF loses phase information when the subject is in focus (and when near focus in the circle of confusion). The on-sensor PDAF therefore can't track a moving subject and keep the subject in perfect focus all the time; it must let the focus drift off enough to get new phase information to re-acquire focus. http://www.clarkvision.com/articles/understanding.autofocus/ 