[rollei_list] Re: Two photographers and Rolleiflex
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Mon, 25 Oct 2010 17:18:44 -0700
----- Original Message -----
From: "Don Williams" <dwilli10@xxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Monday, October 25, 2010 4:40 PM
Subject: [rollei_list] Re: Two photographers and Rolleiflex
Before we moved I had one of the retro reflectors sitting
in the
corner on a book case. No matter where you were, when you
looked it
it looked back at you. Very strange sensation.
DAW
These are called corner reflectors and are commonly
used in surveying because they will reflect a laser directly
back to its source without careful alignment. These are
usually three dimentional so that they are immune to
vertical as well as lateral mis-alignment. A similar
arrangement is used in the reflecting jewells used in
traffic signs so that they reflect on-coming headlights
right back to the driver and look very bright.
One can make a non-reversing mirror out of two flat
mirrors by simply mounting them in a 45 degree corner. first
surface mirrors work best but the effect can be seen with
plain flat mirrors. When you look into one you see yourself
as others do rather than being reversed right to left. If
your not used to it you may not even recognize youself.
Another feature is that when the miror is panned sideways
the image does not move.
Corner reflectors are discussed in many books on
optics.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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