1. Three Pillars of
Photography
Photography

2. Three Pillars of
Photography
• Aper ture
• Shutter Speed
• ISO (film speed)

3. Aperture
• What is Aperture?
• A hole within a lens through which light
enters a camera body.
• The aperture of a camera lens operates like
the pupil of a human eye.
• The larger the pupil the more light enters the
eye. The smaller the pupil the less light
enters.

4. • Small Pupil = Large
f-stop number
• Large Pupil = Small
f-stop number

5. Aperture as F-stop
• F-stop number is the ratio of focal length to
effective aperture diameter. To determine a
camera's f-stop you need to divide the
camera lens diameter by its focal length.
• Focal Length: Distance from front of lens to
camera sensor when subject is in focus.
• Focal length is stated in mm on the camera
lens. A prime lens has a fixed focal length
while a zoom lens shows a range of focal
lengths.

9. F-stop continued
• A camera with a lens diameter of 50mm and
a focal length of 10mm would be f5 because
the ratio is 50/10.
• To change the f-stop would require a change
in lens diameter by adjusting the aperture.
30mm diameter and focal length of 10mm
would be f3 because the ratio is 30/10.

12. F-stop continued
• A large f-stop number means a small
opening and lets in less light.
• A small f-stop number means a larger
opening and lets in more light.
• An f-stop like f1.7 is referred to as "wide
open" and is considered "fast" because it lets
a lot of light into the camera and allows for a
faster shutter speed.

13. • What is Depth of Field?
Depth of Field
• It refers to the amount of an image that is in
focus and is directly impacted by the
camera's aperture.
• The smaller the aperture (represented by a
large f-stop number like f14) the more of the
image will be in focus.
• A larger the aperture (f1.7) isolates an
object from its surrounding by making them
blurry.
• This is referred to as a "shallow depth of field"

14. f1.7 f14

15. An example of a shallow depth of field.

16. Bokeh
• Pronounced "boh-kay", it refers to the
aesthetic quality of blur in the out-of-focus
parts of a photograph.
• Term originates from the Japanese word
"boke" which means "blur" or "haze".

17. An example of course bokeh and shallow D.O.F.

18. You've just learned
about aperture,
f-stop, focal length,
depth of field, and
bokeh.