[Tfug] Way OT: optics mumbo jumbo

Bexley Hall bexley401 at yahoo.com
Tue Mar 25 14:37:12 MST 2008


Hi, Joe,

--- jblais <joe.blais at pti-instruments.com> wrote:

> > > >Often, my solution is to back away from the
> item
> > > >(light falls off as the square -- or cube? --
> of
> > > >the distance) until the reflections are
> manageable.
> > >
> > > Inverse 4th power (x^(-4)), because the light
> makes
> > > a round trip
> > > from a light-dispersing object.
> 
> Well -- I think the exposure setting for the camera
> taking a picture of an
> object, only depends on the distance of the light
> source to the subject.
> The camera can be anywhere, so it's really just the
> inverse-squared law.

But doesn't the light then have to make it's
way *from* the object *to* the camera?  I.e.,
(thought experiment), if I was sitting on the
MOON trying to take a photo of that object
sitting (on Earth) in my family room, wouldn't
there be far less light reaching my lens??
*Regardless* of how close the light was to the
subject??

--don


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