My ophthalmologist was very surprised when I told her I look through my camera’s viewfinder with my left eye. And frankly, I never really thought about it, but I have always used my left eye, with every camera I’ve owned, going back 50 years.
My left eye is nearsighted; everything in the distance looks fuzzy and a little doubled. My right eye is farsighted, and I can see fairly well in the distance without any help. But when I look through my camera’s viewfinder, the image is very clear through my left eye and fuzzy through my right eye.
I was under the impression that a viewfinder shows you what’s in the camera’s “frame” without changing anything. But apparently it corrects my left eye’s nearsightedness and screws up my right eye’s farsightedness.
I am not an eye doctor, but don’t people usually have a dominant eye? What happens when you do the old finger test, where you hold out your finger/thumb over a distant object and then alternately close each eye? With which eye closed does the thumb appear to jump to a different location?
As for the viewfinder, it’s either a mechanical lens/prism setup or a digital viewfinder… maybe it refocuses light onto a single plane (the viewfinder), such that what you’re focusing is not the objects themselves but the gathered light in the viewfinder? I dunno.
It’s a Nikon D90, and thanks for pointing out that little dial. I’ll definitely play around with this tomorrow; maybe I’ll have to switch eyes after all.
(I have found it in the manual. It warns you to “be careful not to put your fingers or fingernails in your eye” when using the dial.)