eli5, how is it that cameras can see clearly underwater whereas human vision gets blurry?

Question

eli5, how is it that cameras can see clearly underwater whereas human vision gets blurry?

In: 245

Answer 1

Cameras underwater generally have a flat surface through which the light passes before entering the lens. This means there’s no effect on the focus of the lens and it can work as normal (though there is a slight magnification effect).

The front surface of an eye is curved and light passing in from the air is focused. Light passing from water into the eye is focused much less, because water and your eye’s lens are very similar, meaning light is bent less. You can fix this by wearing goggles or a mask with a flat front surface and air inside. Now the light is entering your eye from the air inside the goggles and focusing works normally (again, with some magnification).