Week 4 – Light and Exposure

Needed for this class

• Camera or cameraphone
• White and black cards or paper

Light Quality

Light is either direct or diffused.

Direct light: the light strikes the subject from one angle and creates sharp shadows. Sunlight is an example of direct light.

Diffused Light: the light hits the subject from many angles and creates soft shadows. The light is diffused on an overcast day or in the shade.

Measuring the Light

Exposure is the amount of light that comes into the camera to create the photograph.

Exposure is made up of three components:

1. ISO-Sensitivity to light.
2. Shutter Speed-the length of time that the camera’s shutter is open during the exposure. (For more on shutter speed)
3. Aperture-how wide the cameras lens opens to allow the light to come in. (For more on aperture.)

All three are measured in stops.

How your Camera Meter Works

Acronym: TTL – Through the Lens

The meter in your camera is a reflected-light meter.

A reflected light meter averages the tones in the scene and selects the aperture and shutter speed values that will make the whole scene medium gray.

Watch from :45 to 1:34 for an explanation of how your camera meter works.

Using Exposure for Creative Effect

Sometimes, you don’t want the tones in your image to average out to a medium gray. You want to tones to be low key-mostly dark or high key-mostly light.

How to control exposure

With a cameraphone: Touch the area where the main subject is and then drag the little sun icon up or down to increase or decrease the overall exposure.

With a camera: Use Exposure Compensation to take the two photos.

Exposure Compensation-a way to force the camera to make an exposure either lighter or darker than the meter reading. Good for backlight or extremes of light and dark.

Lab Exercises

Lab Exercise: How your camera meter works

Lab Exercise: Using Exposure for Effect

Homework Due Next Class