How does the eye know when the image is in focus? There is distance measuring device, only light entering the eye. No outer feedback to be sure that focus is in fact focus not something the eye think is focus.

Question

Thank you all for your respons and upvotes.

I can now see and focus on the answer of my question 🙂

In: 3993

Answer 1

Your eyes don’t actually record the whole frame of view. It takes many smaller snapshots of information and your brain uses them to create images. Focusing means you are taking in more data on a smaller area, when you are focusing your brain is filling in the background with old data, and maybe tracking large movements and such in the background for small changes. This is how magicians trick us, just because you are “watching”, doesn’t mean you see everything in view all the time. So you are right we don’t know the difference between focus and an illusion, but it has to be good to trick our experience. Kids have little experience, so illusions work well on them. As we gain experience, our brain can use that past data to better determine if we are actually focusing on something or being tricked. Movies for example use forced angles, so because we have to watch from a forced perspective their tricks work really well. Walk a movie set while filming and you aren’t tricked, because you can compare data from different perspectives.

The brain is a data processor and controller. It decides what focus means to it.