Eli5 why do wee see things we dont focus on blurry ? Why cant our eyes see everything sharp ?

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Eli5 why do wee see things we dont focus on blurry ? Why cant our eyes see everything sharp ?

In: Biology

3 Answers

Anonymous 0 Comments

Our eyes work by using a lens to focus light onto a light sensitive area at the back of them. Because a lens can only have exactly one distance in focus at a time, light from every other distance is either over focused or under focused causing it to be blurry. In practically there is a thin slice of distances that appear in focus but you can’t have everything from infinity to right in front of you be in focus at once.

Anonymous 0 Comments

It’s because the pupil of your eye is not infinitely small. This means that one side of your pupil is seeing the world from a slightly different point of view than the other. The lens of your eye can correct for the difference, but only for objects around a certain distance away.

In dim lighting, your pupils are large and this makes more things out of focus; photographers call it having a shallow depth of field. Outside, on a bright sunny day, your pupils shrink and much more of the world can be in focus at the same time. A pinhole camera sees everything in focus, at the cost of only having very dim images.

Anonymous 0 Comments

apart from what others have said, we’ve also evolved from carnivorous/omnivorous ancestors that practiced endurance hunting. One adaptation we’ve made are forward-facing eyes commonly seen on other omnivorous or carnivorous predators such as wolves, tigers, and bears, as opposed to side-facing eyes commonly found on omnivorous or herbivorous prey such as donkey, bison, elk, boar, etc. Forward-facing eyes have a point to allow us to focus on one thing to chase and remain focused on, where as side-facing eyes have a wider field of vision optimized to detect movement, but isn’t as clear.