Choosing Film Format
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Each type of camera has its virtues and
limitations, so choosing one depend on the functions that are to be
performed.
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Many articles have been published in
support of the larger film sizes on the premise that they afford better
quality. Basically, this is correct. A larger film requires less
subsequent enlargement to yield a print of a given size. Therefore,
there will be less degradation of image quality due to the enlargement
of film grain structure, and minor faults in focusing and camera
handling will be less obvious in the final print. However, many of the
authors of these articles have used the area method of calculating
magnification-which has more to do with the computer-related notion of
packing "bits" of information into a given area than with photographic
magnification.
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The area of a frame of 35 mm film (1 x 1
.5 inches) is 1.5 square inches, whereas that of 2.25 x 2.25 inch film
is a little more than 5 square inches; that of 4 x 5 inch film is 20
square inches and that of 8 x 10 is 80. Thus, in reference to area
magnification, 2.25 x 2.25 inch film yields a frame that is 3.5 times
as large as that of 35 mm film, 4 x 5 inch film yields an area that is
13.5 times as large, and so forth.
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However, in reference to linear
magnification, which is what affects the visibility of grain structure
and other image artifacts, 2.25 x 2.25 film is only 1.5 times as large
as the long dimension of 35 mm film. Even the long dimension of 4 x 5
inch film is only 3.5 times as large, and that of 8 x 10 inch film is
6.5 times as large rather than the 53 times that is calculated using
the area method. It can be argued that it is not worthwhile to change
to a larger film size solely for reasons of quality unless linear
magnification can be at least doubled. Further, the handling ease of a
smaller camera may be more important than image quality in many uses.
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