magnify the subject to a greater degree than the
focal length would normally determine.
Zoom lenses are lenses of varying focal length.
They are labeled as a range, e.g., 28–80 mm. The
purpose of the zoom lens is to replace multiple
focal lengths with a single lens. However, visual
quality will almost always fall short when com-
pared to a fixed focal length lens.
Macro lenses are lenses of normal or longer
focal lengths that are designed to focus at a much
closer range. This allows the lens to be within
inches of the subject for much greater subject
magnification than conventional lenses. Macro
lenses are also optically corrected to focus criti-
cally in high magnification.
Exposure
The shutter speed and aperture needed to cap-
ture a given photographic image depend largely on
the sensitivity of the film. In the earliest days of
photography, film was considered to be ‘‘slow’’—it
was not unusual to have to make an exposure of
several hours to get any kind of information on
film. Modern films are now so efficient photogra-
phers are able to capture images in fractions of a
second, provided a properly sensitive film is used.
Film sensitivity, or speed, is measured in terms of
ISO (International Standards Organization). The
higher the ISO, the more sensitive the film, where
as lower numbers represent films that are not as
sensitive, or ‘‘fast.’’
Film speed will dictate the shutter speed and
aperture needed to make a good exposure. The
camera’s internal light meter evaluates the amount
of light in a scene. In a manual camera, it will then
give the photographer its recommendation as to
the shutter and aperture settings to use based on
the film’s ISO. Many modern cameras set the ISO
automatically by scanning an electronic code
located on the film canister.
These settings, once determined by the meter,
are interchangeable to a point. For example, if the
camera recommends that the exposure should be
(^1) = 60 @ f/8, the photographer has several choices.
Shutter speed and aperture share a reciprocal re-
lationship. If the photographer wants more depth
of field than f/8 will him, he could use f/11.
However, since he has now cut the amount
of light striking the film in half, he must compen-
sate by lengthening the time. His final exposure
could be^1 = 30 @ f/11, which would produce exactly
the same amount of density as his original light
meter reading.
Metering Systems
Light meters in all cameras are based on an
average. The light meter assumes that the scene
will have equal light areas, dark areas, and mid-
tones. This assumption averages out to a charac-
teristic known as middle gray, or 18% gray. The
light meter places anything the camera is aimed at
in this value. The most common metering system
is to simply average all of the subject reflectance
that is inside the viewfinder. This system is known
as averaging.
However, since not all scenes can or should be
averaged to 18% gray, more advanced 35-mm SLR
systems allow metering choices. Center-weighted
metering places the meter’s emphasis in the center
of the frame. Matrix metering is based on a grid
that is based on a series of typical lighting situa-
tions, such as a bright sky on the top of the frame,
and darker land at the bottom. The camera then
tries to automatically compensate among choices
on the grid. Spot metering, the most precise
method, allows the photographer to specify a
point in the photograph that they would like to
be 18% gray, or take readings off of a highlight
and a shadow and average the two.
Accessories
Accessories for 35-mm are widely available
because of the format’s widespread popularity. In
addition to interchangeable lenses, flashes, tripods,
filters, motor drives, bellows, cable releases, a num-
ber of other accessories are available for the novice
all the way up to the advanced professional.
Flashes
Many 35-mm point-and-shoot cameras have
built-in flashes, as do some 35-mm SLR cameras.
SLR cameras also offer the choice of additional
external flashes, usually connected to the camera
via a top slot called a hot shoe, or into a plug via a
synchronization cord. Depending on the camera,
photographers can employ an additional electro-
nic flash that has a light sensor located on the
flash itself, or one that is more advanced and can
work with the camera’s meter to shut the built-in
flash off at the proper time. These systems are
dedicated and automatic, or TTL (through-the-
lens) systems, respectively.
Tripods
A sturdy tripod allows a photographer greater
freedom when using slower shutter speeds. Tripods
CAMERA: 35 MM