[Tfug] Way OT: optics mumbo jumbo

[Bexley Hall]

Hi, Rob,

--- Robert Hunter <hunter at tfug.org> wrote:

> On Tue, Mar 18, 2008 at 08:49:28PM -0700, TR wrote:
> > On Tue, Mar 18, 2008 at 8:11 PM, Bexley Hall
> <bexley401 at yahoo.com> wrote:
> > >  Now, my naive question:  by doing this, am I,
> > >  to some extent, counteracting the effect of
> > >  "moving away" from the target?  I.e., does
> > >  the magnification I am bringing in to play
> > >  *increase* the amount of light that strikes
> > >  the (digital) film?
> > Yes and no. as you move away the light returning
> from the subject
> > lessens.  But the camera is always trying to make
> the average light on
> > the film plane the same.  So it either it pumps
> more light to the
> > flash. opens the appeture to let in more light.
> 
> Hi, Don.
> 
> You can also decrease shutter speed to get more
> exposure, but you may
> need a tripod to prevent motion blur.  Increasing
> ISO also helps to
> some degree, but I am not entirely familiar of when
> it is or isn't
> useful.  Keep in mind that a larger aperture will
> reduce your depth of
> field; but by the sound of it, that may not be a
> concern for you.

This is just a simple/cheap digital camera.
Note that I used to use a Polaroid to do this
quite successfully hence figured a digital
camera in "moron mode" would do "as well"?

I don't want to have to drag out a tripod or
extra lighting, etc.  I just want to set the
target on a suitably stable surface, step back,
frame the portion of interest and *click*.

E.g., when I want to show someone a particular
bush that I have planted in the yard, I just
wander out, get the sun at my back (hard to
take photos at night!  :> ) and snap away.

I realize close in shots are often problematic
(getting the camera to focus on such short ranges).
But, I often have problems taking pix of *big*
things!  E.g., taking a photo of a slot machine
is a real PITA as it has so many reflective
surfaces -- the glass of the display plane (easy
to work around just by shooting off axis) as well
as all the curvy chrome surfaces that try to make
it look so flashy to players...
  
(sigh)  So far, I've been able to get all the
shots I have wanted over the years.  But, I
would like to be able to do it "first time"
instead of having to dick around tweeking
things until I get something suitable...

--don



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