Thank you all for your respons and upvotes.
I can now see and focus on the answer of my question 🙂
In: 3993
There is continuous feedback from the brain, which guides the focusing in the eye. Without that, you’re right, the eye doesn’t “know” what to focus on. To see this, look at an object that’s close to you. Now, without changing your head or the direction you are pointing your eye, you can focus on an object in the distance. It’s your brain that is telling the eye what to focus on.
Your eyes are controlled by your brain. When objects become sharp and defined by the pattern recognition part of your brain, then it stops focusing.
I’ve wondered this myself and I’m gonna throw out an idea that there is a mechanism within the eye to focus.
My hypothesis is that the light reflected off the back of the retina would cast a halo of light on the inside of the eye. The retina has light cones over the surface that would seem to be outside of the FOV and our visual cortex false colors a large portion of our view.
If this is correct, then maybe as the eye focuses on the source of light, the halo would be tighter in focus. There also might be a difference in where that focus would be based on the distance to the source.
Our brain, cortex, and eyes all seem to be capable of this process.
Just a thought.
It’s simple: it guesstimates based on how clear the image is.
I was looking at an image on my second screen and, because I was unable to focus it AND it looked precisely like being unable to focus an image that is originally sharp, I gaslighted myself into thinking I need new glasses. Then I put in another app that did show things sharply enough that I went “Nevermind!”
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The distance measuring device is your brain and the fact you have two eyes.
The brain calculates the distance of an object by measuring the difference betweem the images the eyes receive.
Close one eye, then the other. Things that are closer shift around more than those further away.
Good post for titlegore. What does the second half of this even mean?
You control what your eye is focusing on. If something isn’t sharp you change the focus. You might not realize this, because its so engrained you don’t even think about it. I can control the focus of my eye and make things out of focus if I want to, and I’m sure you can to
In the once-popular single lens reflex camera the image from the lens was projected onto a ground glass screen. You focused until you saw good edge definition at whatever range the subject was at. As I recall, the brain is good at determining when the eye has good edge definition re: the object I am looking at. If I am looking at something at arm’s length the tree on the horizon is out of focus. The firmware does not appear to be open source, so I dunno how it works.
There is the possibility that we have a distance measuring device but we have not found it yet. But, at the current level of knowledge it would be our brain adjusting for distance. It is not something I would subscribe to, and I would encourage anyone thinking about this to maybe find that measuring device.
Obviously that would require your eyes sending something out and recieving the reflected signal, instead of only recieving. If eyes are only recieving then there is only your brain to do the focusing. However, I haven’t found myself in a situation where I could consciously control the focusing. I can control it by lookin at things which are at different distances but I could never focus on things by thinking “I want to focus on that right now”. I look at it, and my focus shifts. That isn’t really a conscious mechanism. But make of that what you want.
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