Figure 1-34.–Angle of view.
In figure 1-34, the diagram shows the different
angles of view you can expect from several common
focal-length lenses used with 35mm SLR cameras.
Table 1-4 can be used in selecting lenses for one film
format that provides the same angle of view produced
by another film format and the lens focal-length
combinations.
To use this table, select the lens for one film format
that provides the same angle of view produced by
another film format and focal-length combination.
Example: The angle of view of a 360mm lens on a 4x5
camera is 19 degrees. To match the angle of view
approximately with a 35mm camera, a 105mm lens is
needed. The normal focal-length lens (50mm) for a
35mm camera provides an angle of view of 40 degrees
(width). You can see from the table that the normal
focal-length lens for a medium format camera
(2 1/4” x 2 1/4”) is an 80mm lens because it provides
approximately the same angle of view (38 degrees).
TYPES OF LENSES
There is a large variety of lenses available for most
hand-held cameras on the market today. These lenses are
used for different photographic applications. The types
of lenses you may use in the fleet are as follows: wide
angle, ultra-wide angle, rectilinear, macro, normal focal
length, telephoto, and variable focal-length, or zoom,
lenses.
Wide-Angle Lenses
Anything less than 40mm in focal length (for a
35mm camera) is considered a wide-angle lens. Again,
we are speaking of the lens focal length as it applies to
35 mm cameras.
A wide-angle (short focal length) lens is designed
to take in a large view and is indispensable when
working in confined spaces or when you want to cover
a large area. Wide-angle lenses have their own qualities,
causing apparent, repeat, apparent, distortion and
foreshortening of perspective, so objects close to the
lens appear large, while background objects diminish in
size dramatically.
Many photographers choose a 28mm lens for their
35mm camera wide-angle lens. This is partly because
this focal length allows the typical wide-angle effects
without introducing apparently distorted images, such
as bent walls. As well as providing a wider field of view,
wide-angle lenses also produce great depth of field at all
apertures.
Short-focal-length lenses do not, as is often
believed, actually change perspective. The close view-
points allowed by wide-angle lenses can cause
perspective effects that appear distorted but are
perfectly natural ways of seeing objects at close range.
A wide-angle lens magnifies features nearest the
camera To fill the frame when photographing people
with a wide-angle lens, you must move in close. This
causes a distorted view. But wide-angle lenses can be
used when special effects are desired, such as deliberate
distortion, when exaggeration of features or when
surrounding areas add to the viewer’s understanding of
the subject.
A lens hood, or lens shade, is an important accessory
for any lens. It is especially important with a wide-angle
lens. Strong light can easily cause flare when reflected
internally between the elements of the lens, and unless
you take proper precautions by using a lens hood, your
pictures may be spoiled. Sometimes you are able to see
flare or ghosting in the viewfinder, but more often than
not, it is not visible to the human eye, and it only shows
up on the processed film.
Another precaution to take with wide-angle lenses
concerns filters and other accessories attached to the
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