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Depth
of field:
Your camera's ability to stop down the lens while still
allowing you to see
through the viewfinder is an important feature. With this depth of field
preview, you can tell what will be in clear focus when the shutter
is
released.
If you are using
a small aperture (f/16) you can also see the "hot spots" in the image.
This may help you judge if there is too much contrast in the scene for
the film to handle.
Tripods are
a necessity. The bigger and the heavier the more stable. Unfortunately,
they are also more difficult to carry. Nevertheless, the more
stable the tripod, the sharper the image. A good tripod head
is also a necessity. Hand held shots are generally throw aways
unless you are using image stabilized lenses.
Quality
of light:
Look for good light then look for something to take a picture of. The
quality of the light near dawn and sunset is generally the best. It has
a warm (red,
yellow, orange, cherry) quality that enhances most subjects. During the
day, most of the light has a blue cast to it because the sky serves like
a large blue umbrella which reflects blue light on everything. This is especially
true for objects in the shade on a sunny day. Most of the light in the shade
is blue light reflected by the sky. Scout things out during the day. Shoot
near sunrise and sunset.
Teleconverters do
cost you a stop or two of light but they do not increase the
depth of field at all. So if you have a 2X teleconverter and
the camera says it's f/8, from the depth of field is the same
as your lense at f/4 without the teleconverter.
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Setting Exposures:
Camera
meters are
set by their manufactures to "assume" that
the light coming through the lens (TTL)
is on average 18%
of the light hitting the
subject. The reason that they calibrate
meters this way is that 60% of things
on the planet
reflect
close to 18% (middle toned) of the light
that hits them. Therefore auto exposure
works correctly
for
about 60% of the objects in the world.
Unfortunately, the light toned and dark
toned subjects won't
be exposed correctly if you leave it up
to the camera.
The camera will try to turn everything
to middle tone. It will under expose light
toned subjects
because the camera thinks it's seeing
18% of the reflected light but for white
objects the
camera
may really be seeing 90%. Since the camera
assumes the 90% reflectance is 18% it
thinks that it can
choose a shorter shutter speed and get
properly exposed image. The shorter shutter
speed will
result in less light reaching the film
and that will result
in turning the white object to gray. Therefore,
if you use the camera's meter you must
compensate for the meter's unbending assumptions.
Following
our example of exposing for a light toned
object, since the camera will select a
faster shutter
speed than what is really needed you must
compensate by
adding more light. This can be done by
lengthening the shutter speed or by opening
up the aperture.
Generally for snow to come out white instead
of gray, you have to over expose from
the meter's suggested
exposure by 2 stops.
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