Originally posted by denizenx
hi is Single Lens Reflex tech counted?
otherwise we would be using bubble viewfinders like cheap cams and/or using those old MFs where u look through the hole before mounting a plate there...
otherwise maybe it shd be phase detection AF, in low light where the eye cannot really see properly.
imho, all the other techs add to the convenience but not essential...
There's still the rangefinder...., which Leica users swear by.