Making
Neutral Density Filters to
understand Exposure
120 transparency
film ( slide film that produces positive images) can be used to make
a set of ND filters. Expose the film so that the exposure of each frame
is one stop darker. Take a light meter reading and position Zone V (
mid grey) on frame 6
Units
of light |
2048 |
1024 |
512 |
256 |
128 |
64 |
32 |
16 |
8 |
4 |
2 |
1 |
Zone |
0 |
I |
II |
III |
IV |
V |
VI |
VII |
VII |
IX |
X |
XI |
Frame Number |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
Aperture |
f1.4 |
f2 |
f2.8 |
f4 |
f5.6 |
f8 |
f11 |
f16 |
f22 |
f32 |
f45 |
f64 |
Sheets of smoked glass can also
be used as a means of extending exposure times.