Hi there,

I just got my first Nikon camera - an FM2. I have a question about the AI system's precision for meter readings.

I realize that the system calculates exposure based on the position of the AI lever/ring on the camera body. ie if the ring is in a particular position the camera knows how many stops away that is from the maximum aperture, and adjusts the exposure reading accordingly.

However, I am wondering how finely the ring positions are graded. Does the ring position only convey information to the meter in half stop increments? In other words, if I put the camera a third of the way to F8 from F5.6 will the meter read this as a half stop between the two (F6.7) or is it able to detect an aperture of F6.3? I ask because I am used to using 1/3 stop increments on my RB67, but not sure if I need to be quite so precise with the FM2.