Minarets and mirrors

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Trevor Cunningham asks:

Additional Details: Taken in Aswan, Egypt from our hotel room. This was
a frustrating shot for me. Andy, I think you'll be best to describe what
I'd like to know. I thought that the image on the mirror would have the
same focal length as the mirror itself. However, if I brought the mirror
into focus, I lost the minarets, and vice versa...I decided that the
minarets were more important. I'm not a physics man myself, but could
someone explain this to me? 

An image does not have "focal length" - a lens or a (curved) mirror has.
(It looks as though you are misusing "focal length" to mean "distance
from a lens/mirror", which is quite a common confusion, I think.)

Anyway, the mirror is flat, so its "focal length" is infinity, i.e. it
has no effect on the image, other than reflecting it in the plane of the
mirror. So the distance to the minaret is the distance from the camera
to the mirror, plus the distance from the mirror to the minaret. This is
a lot further than the distance from the camera to the mirror, which is
why you don't get them in focus at the same time.


The photograph doesn't grab me particularly - I think the most
unsettling thing is the two minarets. Why two? First I saw this as two
reflections of the same minaret, which would be one thing (as it were
^_^), but somehow the two near-identical edifices just seem pointless,
without any structural context. Hope that doesn't sound too much like
pretentious claptrap.

Brian Chandler
----------------
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http://imaginatorium.org/shop/
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