They're taking about the size of the actual box that is the AF point. On the RP, there is the "standard" size box (1-Point AF), which let's say for example at a given distance is the size of a person's whole nose when standing 5 feet away. But the RP also has another autofocus method called "Spot AF" which is a tiny little square, that at the same distance might only be the size of an eye's pupil. That "Spot AF" allows for very precise autofocus on a tiny part of the subject. The posts above are referencing the fact that the tiny box is not available on the R, only the RP at this point.On my 7D2, you can select an individual AF point from any of the AF points, but the spot AF point is only the one centre point. Are we talking about spot AF or single point AF?