The Rangefinder Camera
-
Formerly more readily available in a
variety of sizes and forms, rangefinder cameras are now most commonly
found in the 35 mm format. Basically, these are box-body cameras with
an optical rangefinder mounted on top (or on the side). The rangefinder
is connected to the focusing mechanism and usually incorporates the
viewfinder window.
-
This type of camera is held so that the
eye looks through the rear rangefinder port, the eye port. The
viewfinder, usually the same port, frames the approximate area recorded
by the lens upon the film. As the focusing mechanism is moved, a small
section of the viewed image (produced by additional optics and often
colored by a pale filter) moves relative to the larger surrounding
image. Exact focus is obtained when the two overlapping images coincide
at the decided plane of focus.
-
Some rangefinder cameras have a
horizontal, diagonal, or vertical split dividing the two images. The
focus is correct when lines at the chosen plane of focus cross the line
without any displacement. Appropriately, this is called a split-image
rangefinder. Rangefinder cameras are best suited to photographing
people and fast-moving events, which make focusing on a ground glass a
serious distraction. They are small and light, fast in operation,
relatively inconspicuous in use, and usually have very quiet shutters.
Most, however, are poorly suited to either very close up or extreme
telephoto use, except when quite expensive and cumbersome accessories
are added. There is also the problem of parallax: the viewfinder window
is located somewhat off the central axis of the lens, so the lens and
viewfinder do not see quite the same thing, especially when the subject
is at all close. The more expensive rangefinder cameras have built-in
parallax correction. This operates only down to moderately close
distances, and provides "correction" only for main subject viewing. It
cannot take into exact account the differing foreground-background
relationships in a two-subject viewing situation.
-
To allow for viewing inaccuracies,
rangefinder cameras often show somewhat less in the viewfinder than
will be recorded on the film. Thus, there may be some difficulty in
making really efficient use of the available film area a matter of some
importance in a 35 mm camera where the total size of the film frame is
only 24 x 36 mm (1 x 11/2 inches). Still, some of the finest
photojournalism has been, and continues to be, done with rangefinder
cameras.
-
For telephoto use, many rangefinder
cameras have luminous lines within their viewfinders that correspond to
the areas recorded on the film by lenses of longer-than-normal focal
lengths. For other such cameras there are detachable viewfinders for
each lens. Such viewfinders are frequently used with wide-angle lenses.
-
Extreme close-up and extreme telephoto
lenses cannot be used without a cumbersome and expensive reflex housing
to ensure correct framing and focusing. The rangefinder camera is thus
converted into a rather awkward form of single-lens reflex. For the
price of such housing, you could buy a complete single-lens reflex
camera of satisfactory quality.
-
Do not conclude that the rangefinder
camera is no good. It is just that the real advantage of this camera
lies in the intermediate distance range, and particularly in recording
fast-moving human events.
|