My guess is that our eyes aren’t always aligned all the time, and every once in a while the camera catches the difference.
I swear, though, there are some people whose eyes are rarely aligned in photographs. My brother is one of them. He always has an eye wandering cockeyed.
What’s going on here?
What you’re describing is called “strabismus”. It’s quite common as you surmised and tends to be more obvious when the person is not making an effort to fix their gaze to one point. Hence, in photographs (where people may be staring into empty space as opposed to a particular fixed point), it is more obvious and more prevalent.
Might it also be due to certain shutter mechanisms that don’t expose in an opening circle but in a lateral plane? I know this can cause distortion in moving objects.
Strabismus is one of the genetic problems in my family, and it makes everyone appear as though their looking somewhere else. The eyes lose their ability to cooperate with each other and align together. Every female in my family has one form or another, including myself, I have a lazy eye that presents when I’m tired. My brother has whis problem too. Isnt that wierd, that our (whole) family has it?
>Might it also be due to certain shutter mechanisms that don’t expose in an opening circle but in a lateral plane? I know this can cause distortion in moving objects.
Focal plane shutters, common in 35 mm SLRs, expose with a slit that travels across the film (though the slit can be much wider than the film, and this isn’t a very tidy definition or explanation).
Someone whose glance is shifting, but whose eyes point the same way as each other at all times, can appear crosseyed or walleyed or otherwise if the slit photographs each eye at different moments.
I agree with your high-level explanation of shutter action but shutter speeds are commonly down in the hundredths of a second range (can be in the ten thousandths), rarely slower than tenths of a second for flash work. I think most SLRs use 1/90 second for auto flash mode. It is not likely that the shutter would expose one eye, then the eyes would move in the very very tiny fraction of a second while the shutter sweeps to the other eye, then the eyes stop again as the shutter finishes.
Another possibility is that the eyes are looking somewhere other than the lens. If they are fixed closer they will look crosseyed. However, this does not explain a walleyed look where the two eyes are looking two different directions.