Interesting web site -- pinholes etc.

Jeremy Payne (jeremy@yosemite.npa.uiuc.edu)
Sun, 23 Feb 1997 17:46:44 -0600

Just ran across an interesting set of pages I thought someone might find
entertaining that in an intuitive way explain some things about pinholes
and depth of field:

http://www.exploratorium.edu/light_walk/index.html

Would somebody comment on page 25? He discusses a pinhole in
a reflective surface, and points out that a dark branch that's
obscuring the sun as seen in the pinhole image becomes a bright bar
across a dark area in the reflected image, since that's "where the
missing light goes". Now it seems to me that light missing in the
pinhole image where the sun is obscured never made it to the reflective
surface, and that the reflection ought to just have a dark spot,
and not a dark spot with a bright bar, and that therefore there's
probably a more accurate explanation, but then again, I've long since
forgotten my undergrad optics...

cheers,

---------------------------
Jeremy Payne
UIUC Neuroscience program &
College of Medicine
jrpayne@uiuc.edu
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