eli5 Why do camera lenses need to focus on something? Why can’t they just render an image in which everything is clear?

Question

Or maybe only some types of lenses work like that?

In: 281

Answer 1

You can do this. The device you need is called a “light field camera”. This [article on one](https://www.cnet.com/tech/computing/lytro-illum-changes-the-focus-of-a-picture-even-after-youve-taken-it/ ) talks about artistically adjusting focus after you’ve takel the picture, but “all in focus” is a choice.

The camera is mome expensive and the pictures take a lot of bits to store, so this isn’t going to be the default.