# Photograhing our mirror image

1. Oct 31, 2010

### Pranav Jha

If I wish to take a picture of your image while standing 5 m in front of a
plane mirror, for what distance should I set your camera to provide the
sharpest focus.

I guessed the answer would be 10m (distance of object+distance of image). But i don't know why the focus of camera would be sharpest at that distance?

2. Oct 31, 2010

### Staff: Mentor

The light that that enters the camera lens diverges from the image point, exactly as if you removed the mirror and placed the object at that location. The light rays travel exactly the same paths just before they enter the camera, in both cases.

3. Oct 31, 2010

### Pranav Jha

Could you please explain this further

4. Oct 31, 2010

### sophiecentaur

Have a look at this
http://www.physicsclassroom.com/class/refln/u13l2b.cfm" [Broken]

Last edited by a moderator: May 5, 2017
5. Oct 31, 2010

### DaveC426913

Simply put: a mirror will reflect the rays from an object to the camera; but it does not change the total distance. The total distance from object to camera is 10m, thus the camera wants to focus at 10m.

Draw a picture.