So I was taking a photo of the reflection of an exit sign. The sign was about 20ft away. I was shooting the screen of a phone which was about 1 foot away. In order for the sign in the reflection to be in focus, I had to set the focus to about 20ft even though the reflection I was shooting a phone screen that was a foot away. The phone and table it was sitting on were very out of focus including the screen, but the reflection of the sign was crystal clear. Why?
In: Physics
[This](https://i.sstatic.net/9twPx.png) diagram shows the path of two light beams as they bounce off of a mirror. As you can see, the angle that they reflect makes an image which appears to be a distance behind the mirror (the dotted lines).
Because it’s geometry, the visual of the diagram is going to be far more helpful than a wall of text.
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