Nikon Digital body for AI AIS lenses

..The green dot seems a little mysterious at times. I've found that on some lenses it's really pretty accurate, and on others it's virtually useless, and on some it never even appears reliably, and I've never quite determined why. But I do find that it often helps a lot if one zeroes in on it, going past it and then back and forth a couple of times. The closer you can get to the center of its range, the more likely it is to be right

Follow Focus' geared drive

OK, I learned something new! I didn't know these things existed. Thank you.