Week 4

Film, shutter speed, lens aperture
ISO400, 500, F8
ISO200, 250, F8
ISO100, 125, F8
ISO50, 60, F8
ISO25, 30, F8

Film, lens aperture, shutter speed
ISO400, F16, 125
ISO200, F11, 125
ISO100, F8 , 125
ISO50, F5.6, 125
ISO25, F4, 125

Achieve “correct exposure”.
High ISO= image degredation
Rule of thumb: use lowest ISO in a given situation
Film: increases in image grain
Sensor: increases in image “noise”
Film= fixed sensitivity
Sensors sensitivity can be manipulated
High ISO= high grain
Low ISO= finer grain- portraits
ISO100- finer
ISO3200-grain

Exposure- level of illumination
High- faster shutter speed, smaller lens aperture
Low- slower shutter speed, wider lens apertures
- use of a tripod
hand held work (without vibrant reduction technology)
- use a shutter speed at least twice the value of the lens focal length
eg: lens focal length is 50mm, use at least 100thsec shutter speed


Level of subject reflectance:
-camera uses a reflected exposure meter
-measures light reflected from subject calibrated to always render the subject as a mid tone
-auto or manual results in same rendering
-white subject=mid tone rendering
-mid tone subject=mid tone rendering
-black subject= mid tone rendering

Exposure modes:
-average- entire field of view is averaged
-evaluative- interprets scene based on data base
-centre weighted- majority of measurement in centre
-spot- majority measurement in small area
White wall- 125sec @f9 not 125sec @f22