Minolta IIIF - Page 26

Color-compensating filters adjust the quantity of only a single quantity of light, such as red, blue,
or green. The CC index provided by the Color Meter IIIF indicates the nominal density of the green
(G) or magenta (M) CC filter required. Both of these filters adjust the quantity of green in the
illumination; since magenta is the complementary color of green, it can be thought of as “minus
green’. Indications for other CC filters are unnecessary, since the light-balancing filters adjust the
quantities of red and blue in the illumination. CC filters are specified by their nominal density; for
example, a CCO5G filter would be a green filter with a nominal density of 0.05.
Filters can be placed either in front of the light source, or behind or in front of the camera lens.
Light-source filters affect only the light from the source they’re placed in front of; thus, they can
be used to balance the light from several sources to a single value. in addition, since they are not
in the optical path between the subject and the film, they do not affect the image quality at all; also,
exposure compensation is not necessary, even when using a handheld meter. However, they can
be tedious to work with when using multiple light sources; in addition, the range of filters available
is not as wide as that of lens filters.
Lens filters may be somewhat easier to use. However, since they are between the subject and
the film, they must be of higher optical quality. All lens filters must be handled carefully and kept
clean, since scratches, fingerprints, dust, etc. on the filter will degrade the image. In addition, the
color dye in lens filters may reduce the image sharpness, especially for filters with high density; for
this reason, combining more than two or three lens filters is usually not recommended. Lens filters
affect the overall color of the entire scene; when several sources are used, a compromise filtration
pack must be determined if the color output by all sources is not the same.
Exposure compensation must also be considered when using lens filters. If exposure is determined
using a handheld meter, the exposure compensation for the lens filter or filters being used must be
calculated and the exposure adjusted accordingly; when using a camera’s TTL (through-the-lens)
meter, this is not necessary. Exposure compensation is usually listed in the literature accompanying
the filter; the table on the back of the Color Meter IF also lists compensation (+EV) values for LB
and CC filters. When using more than one filter, the required exposure compensation is the sum of
the compensations for each filter. For example, when using an 82B filter (compensation: +2/3EV)
together with a CC10M filter (compensation: +1/3EV), the total required exposure compensation
would be +1EV.
Occasionally, both light-source and lens filters must be used together. This is particularly true
when using different types of light sources. In this case, light-source filters are used to balance all
of the light sources to a single value; lens filters are then used to correct that value for the film
being used.
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