Focus On Lighting Photos Focus on the Fundamentals.pdf

fish. This is just one example,
one where we could equally
well decide to capitalize on the
polarized reflection or get rid of
it. Another example is the blue
sky. In bright sunlight, the sky has
both polarized and unpolarized
reflection. Remembering that the
unpolarized reflection conveys
color, we put the polarizing filter
over our lens and rotate it for
maximum color. This makes
the sky much bluer without
significantly affecting the color of
the rest of the scene. Too brief a
discussion, but enough that we
can start using the principle right
away. For a slightly more detailed
discussion of polarized light, see
the book Light—Science & Magic.
Polarizer or Polarizing Filter:
Depending on the angle of
rotation, can either increase or
decrease the amount of polarized
light making the exposure. May
be of high-quality optical glass
to attach to the camera lens or of
low optical-quality plastic to hang
in front of lights. (Beware of the
low-quality sheets; some work
very well, others offer hardly
any polarization at all! Try to
get a small sample piece before
buying.) See Polarized Light.
Popup Flash: Flash built into a
camera that is generally out of
sight when not needed but that
can be opened when needed.
Postproduction: Work
done on images after they
are captured. It may include
burning, dodging, vignetting,
color adjustments, and cropping.
Used to all be done either in
the darkroom or by hand on
prints, but now almost always
done with software. A very small
percentage of this work can still
be done better and more quickly
on the print, however. Learning
to work without the digital tools
is a fairly tedious process most
photographers don’t want to
master. Still, it’s a good idea
to become acquainted with
someone who can do this, just in
case you need him or her.
RAM: Random access memory.
Most people already know this
concept, but we need to mention
that digital image processing
is extremely RAM intensive.
Whatever RAM we need to
rapidly operate word processing,
spreadsheets, and presentation
software simultaneously may
become impractically slow when
we start to process images. Equip
your computer with all the RAM
you can afford if you intend to
process pictures on a regular
basis.
Raw: Often written “RAW,”
because many photographers
consider it to be a standard
image format like TIFF or JPEG.
Not so; one camera maker’s
raw can be totally different from
another’s, and the specifications
may be proprietary and secret.
A better format is Adobe’s DNG
(digital negative) format, because
its code is open to all. A few
(almost always among the
better) camera manufacturers
have adopted DNG rather than
developing still another raw
format. Other very good camera
makers persist with their own
proprietary raw formats, and
there’s no way to predict whether
this Babel will continue or evolve
into a common, universally
available format. All of these
file formats allow an image file
with a wider dynamic range
that can be used to produce,
say, a TIFF. They preserve
the data with minimal loss of
information. (DNG compresses
with no loss of information.)
A resulting 24-bit TIFF, with its
more limited dynamic range will,
indeed, lose information, just as
photographers have always lost
information when they made
a silver-based print. Still, all of
the raw formats and DNG allow
photographers to change their
Glossary 193