Why whenever you take a picture of a computer screen, you can see all the pixels?

Question

Why whenever you take a picture of a computer screen, you can see all the pixels?

In: 5

Answer 1

What you are mostly seeing is moire patterns [https://en.wikipedia.org/wiki/Moir%C3%A9_pattern#/media/File:Moir%C3%A9_pattern.png](https://en.wikipedia.org/wiki/Moir%C3%A9_pattern#/media/File:Moir%C3%A9_pattern.png)

It happens because you are projecting one grid of pixels on the screen onto another grid of pixels in the camera sensor. They are not going to match up perfectly. And they are of similar pitch. That interference is what you are mostly seeing. The effect goes away if the mismatch between resolutions is great enough or the image is slightly defocused.