| Many photographers rely totally on
their camera’s built-in light meter. After shooting many rolls of film they
can’t understand why their pictures are not 100% exposed correctly! Your camera may
say automatic, but that does not mean automatically right! Any good photographer must
learn to "out think" the camera’s meter. To accomplish this an
understanding of the "Sunny f 16" rule is essential.
So what is the rule? Well, simply put, the rule tells us on a bright sunny
day to set your aperture at f 16 and convert the ASA or ISO film rating to the closest
shutter speed.
I.e. Ektachrome 200, f 16 at 1/250...Fuji
50, f 16 at 1/60, etc. Now believe me, this rule works! You can travel the world with or
without a light meter and get 100% exposure results but only if your subject is
larger than a bread box, is front lit and has
average tonal brightness.
As with most photography, there are some variables to keep in
mind. First, the sunlight must be bright, with little or no haze. If you’re shooting
on sand, snow or with a bright building around, you will have to stop down. On the other
hand, if you are shooting on a cloudy or overcast day, you will have to compensate by
opening up. If your subject is not front lit, i.e. back lit, side lit, etc. you will also
have to make exposure compensation (see the variable chart). Keep in mind your
subject’s tonal brightness. A white or light colored subject requires less exposure
than a dark subject. Remember that your in-camera exposure meter is calibrated for average
subject tonal contrast of approximately 18% gray. When the meter reads a scene, it tells
your camera to exposure the subject as an average tonal scene. You as the photographer
must learn to see your subject’s brightness and expose correctly..
Once you know and understand the variables of the
"sunny f 16 rule" you can begin to "out think" your camera’s
built-in exposure meter. In fact, the rule comes in handy to check the accuracy of all
your light meters.
I know a lot of professional photographers who don’t
use light meters at all. They have the ability, in the studio or on location, to see the
subject’s tones, the subject’s lighting, the subject’s size and then
compute the correct exposure, given any ISO rating, in their head. This takes years of
experience and begins with a thorough understanding of the "sunny f 16 rule".
One last point, the rule holds true for both negative and
transparency films. But keep in mind that negative films have a much wider exposure
latitude than transparency films. Therefore, mastering this rule with slide film is the
best test.
Sunny f16 Rule Chart
| Variables: |
Average Subject |
Light Subject |
Dark Subject |
| Front Lit (Full Sun) |
Use Rule |
Rule -1 Stop |
Rule +1 Stop |
| Side Lit |
Rule +1 Stop |
Use Rule |
Rule +2 Stops |
| Back Lit |
Rule +2 Stops |
Rule +1 Stop |
Rule +3 Stops |
Photo
Tips:
a. The most reliable light meter in your camera bag is the
film’s datasheet. Read each datasheet and develop a total understanding of the
characteristics of each type of film you use.
b. Also, when working with new types of film or when just
starting out, get in the habit of recording exposure, lighting and processing information
in a small notebook. Then when you judge your results, you will have a foundation of facts
to make correct decisions.
c. By being organized and developing good habits you can be
reassured as to the final quality of any pictures you take. |
