Topics

ISO, APERTURE and
SHUTTER SPEED
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Easy to Understand and Apply
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Triangle of Exposure
ISO
Aperture
Shutter Speed
Practical use of ISO, Aperture & Shutter
Speed
What shooting mode and why
By John W. Obradovich, PSA
2
Topics
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ISO
Lenses and Focal Lengths
Crop Factor
Pulling it All Together the Easy Way
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Triangle of Exposure
Triangle
of
Exposure
DSLR Camera Simulator
Helpful websites
Aperture
Questions and Discussion

Shutter
Speed
Change in one affects the other two
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Triangle of Exposure
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Triangle of Exposure
Changes in ISO, Aperture, or Shutter Speed
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Measured in a Stop or EV (Exposure Value)
One Stop/EV change:
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ISO
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+ 1 Stop increases the amount of light by 2
- 1 Stop decreases the amount of light by 1/2
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APERTURE
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Size of lens opening
Measured in “f/ Stops” i.e. f/2.8, f/4.5, f/16, etc.
SHUTTER
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Sensitivity of camera sensor
Measured in Speed, i.e. 100, 400, 1200, etc.
Curtain like device that opens for an instant
Measured in Time, i.e. 1/60 sec; 1/500 sec; 2 sec.
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1
Change in Stops
Analogy of Water to Aperture and Shutter

“Valve” controls
how long the
water flows
“Pipe” diameter
controls volume
of water flow

“Shutter” controls
how long the light
flows
Over Exposed – Too much Light
Under Exposed – Not enough light
“Aperture”
diameter controls
volume of light flow
+ 2 stops
“Bucket”
collects
water
“Camera Sensor”
collets light
+ 1 stop
Correct Exposure
- 1 stop
Over Exposed
- 2 stops
Under Exposed
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ISO
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Lower ISO speed decreases camera
sensitivity
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ISO
For use in bright outdoor light
Higher ISO speed increases camera
sensitivity


One “stop” increase is 2 times the ISO speed

One “stop” decrease is ½ times the ISO
speed
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Lower ISO – highest quality
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Higher ISO – increases digital noise as grain
For use in low indoor and night light
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ISO

ISO
Low and high ISO images
Slower ISO Speed -- lower
sensitivity – for use in bright light
100
200
one stop
ISO 200
400
500
640
Higher ISO Speed -- higher
sensitivity – for use in dim light
800
1,600
2,000 6,400
one stop
ISO 12,800 – very grainy
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2
Aperture
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Aperture
Describes the diameter of the lens opening
Measured in ”f” stops
One stop increase doubles amount of light
One stop decrease halves amount of light
F stops vary by 1.41
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Larger aperture -- increases
light through the lens
f/1.4
f/8 to f/11 is one stop decrease (8 x 1.41 = f/11)
f/8 to f/5.6 is one stop increase (8 / 1.41 = f/5.6)
f/2
f/2.8
f/4
Smaller aperture -- reduces
light through the lens
f/5.6
f/8
f/11
f/16
f/22
one stop
Smaller number is a larger aperture because
F stops are fractions! (f/2.8 = 1/2.8, f/16 = 1/16, etc.)
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Aperture
Aperture
Smaller “f stop” number (larger aperture)
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Larger “f stop” number (smaller aperture)
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Diagram of “f stops” and aperture openings
Increases amount of light to camera sensor
Decreases depth of field
Decreases amount of light to camera sensor
Increases depth of field
Most cameras have fractional “f stops”
ie: f/3.5, f/5, f/6.3, etc.
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Aperture
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Aperture
Depth of Field (DOF)
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“. . . distance between the nearest and farthest
objects in a scene that appear acceptably sharp in
an image.” Wikipedia
Sample images
f/2.8 1/2500 sec ISO 100
f/14 1/100 sec ISO 100
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Phrase “stop down” means to choose a
smaller Aperture
Phrase “stop up” or “open up” means to
choose a larger Aperture
f/32 1/20 sec ISO 100
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3
Shutter Speed
Shutter Speed

Length of time, in seconds, that light shines
on the camera sensor
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Slower shutter speed increases light

Faster shutter speed decreases light
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Stop doubles or halves the shutter speed
Slower shutter speed -increases light to the sensor
4 sec
2 sec 1 sec
one stop
1/25
Faster shutter speed -decreases light to the sensor
1/50
1/125 1/250 1/500 /1000
two stops
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Summary of ISO, Aperture and
Shutter Speed
Le
ss
Mo
re
t
th
of
F
Lig
h
De
p
Mo
re
Le
ss
ss
Le
ss
Le

100
Shutter Speed
Blur 1/10 sec
change either of the other elements by - 1 stop
Change one element by - 2 stops

More
Light
Motion
Change one element by + one stop

t
Less
1/1000 sec Freeze
ISO
in
Triangle
of
Exposure
h
Lig
f/18
Change of one affects the other two
elements of exposure
Great advantage for interchangeability of stops

a
Gr
Aperture
6400
re
Mo
re
Mo
iel
d
f/2.8
Practical Use of ISO, Aperture and
Shutter Speed
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change another element by + 2 stops
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or both other elements by + 1 stop
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Practical Use of ISO, Aperture and
Shutter Speed
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Practical Use of ISO
Identical Exposures in Red
Example 1
2 compared to 1

3 compared to 1
ISO increase
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Tv
Av
ISO
Tv
Av
ISO
Tv
Av
ISO
1/125
f/2.8
1600
1/60
f/4
1600
1/30
f/4
800

1/250
f/4
800
1/125
f/5.6
f/5.6
400

800
1/60
1/500 f/5.6 400
1/250 f/8
400
1/125 f/8
200
1/1000 f/8
200
1/500
f/11
200
1/250
f/11
100
1/2000 f/11
100
1/1000 f/16
100
1/500
f/16
0S
+2 S
1/4000 f/16
1/2000 f/32
+1 S
-1 S
ISO decrease

1/1000 f/32
-1 S

-1 S

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Tv = Shutter Speed; Av = Aperture; S = Stop
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Increases light to the camera sensor
Provides faster shutter speed and/or
Provides smaller aperture
Decreases light to the camera sensor
Provides slower shutter speed and/or
Provides larger aperture
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4
Practical Use of ISO

Practical Use of ISO
Typical ISO Speed considerations:
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100 – 200 speed. Outdoors, bright light, indoors
with flash. Highest quality.
200 – 400 speed. Morning, evening, overcast,
motion. Good quality & low grain.
400 – 800 + speed. Fast outdoor motion, indoor
without flash. Lower quality & some grain.
Typical ISO Speed considerations
(continued):
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1,200 – 2,400 + speed. Night time city lights.
Grain may become a problem.
2,400 – 6,400 + speed. Outdoor night time skies.
Grainy photos restrict enlargements.
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Practical Use of Aperture
Practical Use of Aperture
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Aperture increase
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Increases light to the camera sensor
Provides increase to shutter speed and/or
Provides decrease in ISO
Aperture considerations:
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f/2.8 – f/5.6
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Provides higher shutter speeds
Provides very shallow depth of field
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Aperture decrease
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Blurry background
Excellent for macro photos
Good for indoor available light
Decreases light to the camera sensor
Provides decrease to shutter speed and/or
Provides increase in ISO
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Practical Use of Aperture
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Practical Use of Aperture
Aperture considerations (continued):
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f/8 – f/16
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Aperture considerations (continued):
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Outdoors
Indoor flash photography
Provides good quality
Greater depth of field
f/16 – f/22 +
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Requires very bright lighting
Great depth of field
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Foreground and background in focus
Desired for landscape photography
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Practical Use of Shutter Speed
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Application
Shutter speed decrease
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Practical Use of Shutter Speed
Increases light to the camera sensor
Provides decrease in ISO and/or
Provides decrease in Aperture
Shutter speed increase
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Decreases light to the camera sensor
Provides larger Aperture and/or
Provides increase in ISO
Typical Shutter Speed
Night time - stars
10 – 30 + seconds
Night time – city lights
1 – 20 seconds
Blur flowing water
1/30 – 30 seconds
Pan moving people
1/15 second
Pan fast vehicles
1/30 – 1/250 second
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Practical Use of Shutter Speed
Practical Use of Shutter Speed

Application
Typical Shutter Speed
How to select shutter speed for handholding
your camera

Freeze people & animals
1/250 second
Freeze athletes
1/500 second
Freeze fast vehicles
1/1000 – 1/2000 second
Use “Reciprocal of Focal Length Shutter Speed
Rule”
1/focal length = minimum shutter speed
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Freeze birds in flight
1/2000 second
Freeze very fast motion
1/4000+ second
Example: 100mm focal length = 1/100 second
Example: 300mm focal length = 1/300 second
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Practical Use Summary
What Shooting Mode and Why
ISO
100
200
400
800
Shooting Mode
1600
3200
6400
Lower quality/more grain
High quality/low grain
Aperture
f/2.8
4
5.6
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11
Portraits
Shallow Depth of Field
Background Blurred
16
22
1/1000
1/500
1/250
1/60
1/30
1/15
Silky water
1/8
1 sec
Blurs motion
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Your Adjustments
AUTO and SCENE
Modes
P (Program) Mode
Fully automatic – you make no
adjustments
Select ISO. Shutter Speed and
Aperture change is automatic
Tv, S (Time Value/
Shutter Speed Priority)
Select Shutter Speed & ISO.
Aperture change is automatic
Av, A (Aperture Priority)
Mode
M (Manual) Mode
Select Aperture & ISO. Shutter
speed change is automatic
You select all. Aperture, Shutter
Speed & ISO
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Landscapes
Great Depth of Field
Everything Sharp
Shutter Speed
Freezes motion
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What Shooting Mode and Why
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P Mode is highly recommended instead of
Automatic mode.
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What Shooting Mode and Why
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Can adjust ISO for the desired range of aperture
and shutter speed
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Professionals and advanced amateurs use
Shutter Priority, Aperture Priority and some
Manual.

Professionals use Program Mode in crowds.

Change in ISO provides desired aperture and
shutter speed
Provides fast shooting without any additional
adjustments
Better results than Automatic Mode
Preferred because it provides the most control.
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What Shooting Mode and Why
Lenses & Focal Length
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Play with the “Camera Simulator” at
www.camerasim.com
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Shorter focal length = wider angle of view
Longer focal length = narrower angle of view
Try each camera setting, select lighting, zoom,
use a tripod, use P, Tv, Av and Manual modes.
Snap a picture
Learn about Depth of Field for your camera at
www.dofmaster.com
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Actual calculations for your specific camera
Charts can be printed for your camera bag
(Excerpt from www.nikonusa.com)
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Crop Factor
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Crop Factor
35mm sensor is known as “full frame”
Smaller sensors are a “crop” of 35mm

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APS-C sensor provides a virtual telephoto
effect
Example: 100mm lens on 35mm sensor
provides virtual 160mm on APS-C sensor
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
(Image from www.gizmag.com)
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100mm X 1.6 crop factor = 160mm on APS-C
Example: 300mm lens on 35mm sensor
provides virtual 480mm on APS-C sensor
300mm X 1.6 crop factor = 480mm on APS-C
APS-C sensors are a 1.6 “crop” of 35mm
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Pulling it All Together the Easy Way
Crop Factor

APS-C sensor with a 10mm lens has same
field of view as a 16mm lens on “Full Frame”
sensor

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16mm lens/1.6 APS-C Crop Factor = 10mm required on
APS-C sensor
APS-C sensor with a 50mm lens has same
field of view as an 80mm lens on “Full Frame”
sensor
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Many great tutorials at:

www.photographymad.com
www.adorama.com

http://digital-photography-school.com

Adorama TV and Learning Center
Tutorials
Weekly tips via free subscription
80mm lens/1.6 APS-C Crop Factor = 50mm required on
APS-C sensor
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Pulling it All Together the Easy Way
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SUMMARY
Visit CameraSim, DOF Master, etc.
Review your handout
Read your camera manual
Use the variables: ISO, aperture, shutter
speed, etc.
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Best Way to Pull it All
Together
 Go
out and shoot
 Practice,
practice and practice
Revised 9/5/2014
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