Today, I will learn…

� Exposure:

� Aperture

� Shutter Speed

� ISO

� The Exposure Triangle

Learning Goals

Exposure

What is Exposure?

� In photography, exposure is the amount of

light in your image.

� Exposure can be determined by three key

factors:

� Aperture

� Shutter Speed

� ISO

Exposure as a Window

Shutter Speed

Aperture

ISO

Aperture

� Aperture refers to the diaphragm within

your camera lens, and how big or small the

opening is

� The smaller the opening = less light

� Larger the opening = more light

� Measured in f-stops

� Smaller f-stop number = more light

� Larger f-stop number = less light

Aperture

� Aperture also controls your depth of field (how much of the image is in focus)

� The smaller the f-stop (larger aperture) the less or narrower depth of field

� The large the f-stop (small aperture) the more or wider depth of field

More light Less light

Narrow DOF Wide DOF

f 1.4

Shutter Speed

� Shutter Speed refers to how fast or slow your

camera shutter will open to receive light

� It is measured in seconds and fractions of

seconds, for example;

� 1/1000th second = fast shutter, less light

� 15 seconds = slow shutter, more light

Shutter Speed

� Shutter Speed also controls how much motion blur is in your image

� Fast shutter speed (i.e. 1/1000) = less motion blur, sharper image (freezes time)

� Slow shutter speed (i.e. 1/15) = more motion blur, blurrier image (demonstrates motion)

1/15 1/60 1/250 1/1000

More light Less light

More motion blur Less motion blur

15s 8s 4s 1s ½ ¼ 1/8 1/15 1/30 1/60 1/125 1/250

36 minute Shutter Speed!

ISO

� ISO refers to how sensitive your camera’s

digital sensor (or film) is to light

� It is measured in doubling or halving the

previous ISO stop;

� 100 ISO = less sensitive

� 6400 ISO = very sensitive

ISO

� ISO also controls how much grain (noise) is in your image

� Low ISO (i.e. 100) = less noise, smoother/cleaner image

� High ISO (i.e. 3200) = more noise, more grain

More light Less light

More noise Less noise

6400 3200 1600 800 400 200 100

ISO

Exposure

� However, in order to achieve excellent

results, you need to think about all three

exposure elements

� These three elements work together to create

a properly exposed image

� An imbalance of any of the elements can

create an underexposed or overexposed

image

Exposure

Aper

ture

Shutter S

peed

ISO

Exposure

� Underexposed loss of shadow detail

� For example, a picture in a cave, you

wouldn’t be able to make out the contours of

the rocks/stones

� Overexposed loss of highlight detail

� For example, picture of the sky on a bright

day, you wouldn’t be able to make out the

clouds

Practice

� Aperture

� Use Aperture Priority mode

� Place items on a table at different

distances

� Experiment with adjusting your aperture

(f-stop) to focus on the different elements,

and then have all elements in focus