Nikon SLRs Series Instruction Manual page 27

Accessories-Filters
Nikon filters are made of optical glass, ground and polished so that both surfaces are
optically flat and parallel.
Nikkor lenses and Nikon filters are made for each other. For best results, use Nikon
filters on Nikkor lenses. Nikon filters are available in both screw-in and series mounts,
depending on the type of lens.
Since filters cut down on the light passing through the lens, some increase in exposure
time or in lens opening is necessary to compensate for the loss of light. This increase is
expressed as a filter factor. For example, if the filter factor is 2, double the exposure time
or open up the lens one full stop. Filter factors depend on the light source and type of
film. The chart at right shows the filter factors.
No exposure compensation is necessary with the Photomic FTN finder. The built-in
meter reads only the light passing through the lens and therefore compensates
automatically for loss of light.
Black-and-white film
Black-and-white and
color films
Color film
Type
Light
Yellow Medium
Deep
Orange
Red
Light
Green
Deep
Ultraviolet
Polarizing
Neutral Density
Skylight
Light
Amber
Deep
Light
Amber Medium
Deep
Esposure factor
Designation
Daylight
Y44 1.5
Y48 1.7
Y52 2
O56 3.5
R60 6
X0 2
X1 5
L37
L39
Polar
ND 4X
ND 8X
ND 100X
ND 400X
L1A
A2
A12
B2
B8
B12
Tungsten
light
1
1.2
1.4
2
5
1.7
3.5
1
2.4
4
8
10
400
1
1.2
2
1.2
1.6
2.2