Photography: As film speed light meters

2. Film Speeds
 SLOW: Low numbered ISO (50-100)
Very slow reaction to light. Use in bright conditions. An exceptionally small grain means fine detail
will be achieved in the negatives. Useful for static subject matter like still life. May require slow
shutter speeds and wide aperture settings.
 MEDIUM: Approx ISO (100-200)
Used for a wide range of subjects and lighting conditions.
Good compromise between light sensitivity and graininess of the image.
 FAST: High numbered ISO (400-3200)
Quick reaction to light. Good for poor light conditions. Very fast films suitable for evening/night-time
work. Ideal for action shots. Large grains create a more textured, grainy image.
BEWARE!
Do not use C41 process black and white film as
it cannot be used in the darkroom.

3. Film composition
The image tones on a black and white
negative appear reserved, with light areas
corresponding to dark areas of the subject
and dark areas of the negative corresponding
to light areas of the subject.
Film consists of several layers of different
materials such as cellulose and gelatine, but
the layer that causes it to react to light is the
photo-sensitive emulsion which contains
crystals of silver halide in gelatine.
The size of these crystals determines how
quickly the film will react to light – the larger the
crystals, the faster the film and vice-versa.
We need to know this information to set our
camera’s up properly, so this is why we use
FILM SPEEDS.

4. Light Meters
 What is an Internal Light Meter?
To record an image accurately your negative/digital sensor must receive the correct quantity of light to make an exposure. The naked
eye cannot measure brightness reliably so some form of light measuring meter is vital to the picture taking process.
The meter reads the light being emitted by the subject and a reading is shown in the viewfinder.
 This is an example of what you may see in a camera with
a needle meter reading. You change the aperture and speed
in order to line up the two needles on the right of the
viewfinder.
 This is an example of what you may see in a camera with an
electronic meter reading. Generally you change the aperture
and speed settings to balance a glowing LED between + and –
in the camera viewfinder.
 Make sure that your camera batteries are checked regularly.
 Also make sure that your camera is set for the appropriate speed of film that you are using.

5. Setting the correct exposure:
 In order to create a well-balanced exposure on your negative/digital
sensor you need to think very carefully about the amount of light
passing through your camera’s lens. There are two elements which
control the exposure – aperture and speed; each working in
harmony with the other.
In the diagram above this inseparable relationship between aperture (top line of diagram)
and speed (bottom line of diagram) is illustrated. When the aperture setting is
changed, the speed setting will also change to compensate.

6. Re-cap
 What difference does film speed make?
 How does it work?
 How do you change it on your camera?
 Why do you need to use your light meter?
 How do you use your camera’s light meter?
 If you were shooting photograph’s in very
bright conditions what settings might you
expect to use?

7. Make notes:
o In your sketchbook record what you
have learnt so far:
Film speed
Your light meter
How aperture and shutter speed
work together.
o Produce an image/diagram of your own
light meter and label it to show how you
find the settings.