Why is the focus of a reflection the same as the item being reflected and not the item it’s reflected off of?

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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

6 Answers

Anonymous 0 Comments

Oh, ok. Dang, I was thinking only about the two objects and not the “photo” in “photography”. I’m not taking a picture of the sign but rather the light reflected off of it, so the distance to me from the sign is how far its light travels regardless of whether Im shooting it directly or through the reflection. I think I understand. Please correct me if I’m wrong. Thanks for the explanations, everyone!

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