So I need glasses. When I take them off, the world is blurry. I can look through a phone camera and see clearly, but if I look at a mirror, things far away are still blurry. This is probably because of how far the light has traveled as I understand it, but why does that affect how blurry it is?
In: Physics
Mirrors faithfully retain the directions that light particles are travelling in and so flat mirrors don’t form an image. That means that mirrors don’t reset distances for the purposes of focusing. If you stand in front of a mirror 1 metre away, your eyes need a focal distance of 2 metres to look at yourself.
But electronic screens are creating a new image and the light is originating at the screen and spreading out. So you have to focus on the screen and the original distance from the subject to the camera doesn’t matter. The camera lens had to focus on the subject to form the image, but now you have to focus on the image.
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