Lesson 4 • Exposure

1. Today, I will learn…
Exposure:
Aperture
Shutter Speed
ISO
The Exposure Triangle
Learning Goals

2. Exposure

3. 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

4. Exposure as a Window
Shutter Speed
Aperture
ISO

5. 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

6. 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

7. More light Less light
Narrow DOF Wide DOF

10. f 1.4

11. 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

12. 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

13. 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

17. 36 minute Shutter Speed!

18. 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

19. 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

20. More light Less light
More noise Less noise
6400 3200 1600 800 400 200 100
ISO

24. 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
Aperture
ShutterSpeed
ISO

26. 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

28. 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