Questionnaire #3

(week 5)

1. What are the two ways exposure is controlled? And what are some other factors that play a role in exposure?

Exposure is controlled primarily by SHUTTER-SPEED and APERTURE.

2. You have an ISO of 400, a shutter speed of 1/125^th second and an f-stop of F5.6.

a) I ask you to open up the aperture to let more light in by 2 stops. What would you change your reading to? - f/2.8

b) Now, back at your original setting, close down three stops. What is your setting now?

- f/16

3. What are three ways you can measure exposure?

ISO (sensitivity) - Shutter-speed (time of exposure) - Aperture (amount of light)

4. If in a given situation ‘correct’ exposure is achieved by using 125 @ f8 at ISO 100, indicate the new shutter speeds required to provide ‘correct’ exposure for the other ISO settings below.

Film - Shutterspeed - Aperture

ISO400 - f8 - 1/500

ISO200 - f8 - 1/250

ISO100 - 125 - f8 - Correct exposure.

ISO50 - f8 - 1/60

ISO25 - f8 - 1/30

5. If in a given situation ‘correct’ exposure is achieved by using 125 @ f8
at ISO 100, indicate the new f-number required to provide ‘correct’
exposure for the other ISO settings below.

Film - Shutterspeed - Aperture

ISO400 - 125 - f/16

ISO200 - 125 - f/11

ISO100 - 125 - f8 - Correct exposure.

ISO50 - 125 - f/4

ISO25 - 125 - f/2.8

6. When you use a high ISO you get image degradation. With film this is called increasing the size of the grain. With digital we don’t refer to grain, we refer to?

Pixelation - which is a breakup of fine detail and colour.

7. On your camera, what is the difference between AUTO mode and MANUAL mode?

AUTO mode basically means the camera will do it's best to work out "correct exposure" using it's best metering abilities to find the mid tones - the photographer has no control over the camera's adjustment dials.

MANUAL mode is quite different, the camera will still use it's metering abilities to aid with "correct exposure" to find the mid tones - but the photographer has complete creative control of all the camera's adjustments dials.

8. All in-camera meters try to render the scene as a mid-tone. So if the mid-toned scene is rendered appropriately, what will happen to the light toned scene (white)? And the dark toned scene (black)?

With a WHITE (high-key) scene the camera will stop-down the exposure leaving the image looking under-exposed and a little dull and grey looking.

With a BLACK (low-key) scene the camera will stop-up the exposure leaving the image looking over-exposed and a little too white.

9. What type of metering do built-in camera meters use?

Spot metering - for specific areas of the subject or scene, rendering approximately 3% or less.

Centre-weighted metering - which means it will render the middle 80% of the scene and work out correct exposure from that.

Evaluative metering - will render the entire frame and set the exposure automatically.

Partial metering - is quite effective when the background is much brighter than the subject due to backlighting. It covers approximately 7% of the scene's centre area.

10. If you are using ISO200 how more light sensitive will your exposure be if you change this to ISO400? (HINT: This is equivalent to 1 stop)

ISO400 is twice as sensitive to light than ISO200.

D.