Half a century back, no problem. Now digital readout but you are correct once you get your mind on the subject and if it does not keep wandering down memory lane
Also if you can manage shifting between far vision and near vision glasses on the fly
then those digital squiggles do become a snap. That's another matter that on the old cameras the feel of your hands on the rings, you had no need of eyes, could even take a snap in the dark. :crying:
Any way digital or feel, the theory is the same.
Regards,
Masud.