The Exposure Triangle

1
Digital Photography I
Aperture ISO Shutter Speed
2
The Exposure Triangle

• Digital Photography I

3
Exposure
This is by far the most technical lesson of this
session. However it is essential to begin to
get a grasp of the exposure triangle concept.
You must refer to your personal camera manual
in order to completely understand how to use the
creative modes. Be sure to take notes when
necessary.
4
Exposure
Exposure is the total amount of light that you
allow into the camera
5
Exposure Triangle
ISO
Changing any of the three elements will effect
the exposure
Shutter Speed
Aperture
Aperture and shutter speed are inversely
proportional to each other.
6
Exposure Triangle
http//www.flickr.com/photos/robert_d_ellis/538740
8926/
7
Camera Configuration
Digital Sensor
Shutter
Aperture
Lens
8
Exposure

•  
• Too much light results in an over-exposed image
  where there are areas of bright white or
•  blow-outs.  These areas contain no detail or
  color. 

9
Exposure

•  
• Too little light results in an
• under-exposed image where
• there are areas of low detail.

10
Exposure
Great differences in light within a photograph
confuses the camera. The camera exposes to the
bright light , therefore the darker portions of
the photograph are blacked out.
Vatican, Rome
11
Shutter Speed
12
Shutter Speed
Posing for 19th century photographs Usually took
as much a 5 minutes of Sitting perfectly
still. Luckily, today we can control Shutter
speeds.
Opelika, AL
13
Shutter Speed

• Shutter Speedthe amount of time the shutter is
  openwhich determines how much light is captured
  in the recording process
• Measured in seconds super fast 1/2000 second to
  30 seconds
• The slower the speed, the longer light can enter
  the camera. Appropriate for shooting pictures in
  darker situations also great for freezing action
  and movement

Shutter speeds and aperture (f-stops) are
inversely proportional.
14
Shutter Speed
Action shots require fast shutter speeds.
Callaway Gardens Steeple Chase
15
Shutter Speed

• Shutter speed is measure in fractions of a
  second.
• A shutter speed greater than 1/60th second
  requires the use of a stabilizing device like a
  tripod. Without stabilization, the photograph
  will not be crisp and clear.

16
Low Lightrequires longer shutter speeds and a
tripod
Full 1 second shutter speed
Langdale Mill
17
Low Lightrequires longer shutter speeds and a
tripod
18
Shutter Speed
Must use A tripod
Best for Sports shots
19
ISO
20
ISO

• ISO is the measurement of how sensitive the image
  sensor in the camera is to light.
• Measured in numbers 100, 200, 400, 800, etc.
• Use a lower number when smooth crisp images are
  need and you have plenty of light.
• Higher numbers are used when light is limited,
  you do not want to use a flash, or the subject
  is moving may result in grainy images

21
The Exposure TriangleISO International
Organization of Standardization

• ISOthe measurement of the sensitivity of the
  camera
• image sensor to light.
• Measured in numbers 100, 200, 400, 800, etc.
• Lower numbers used when smooth crisp images are
  desired and you have plenty of light.
• Higher numbers are used when light is limited,
  you do not want to use a flash, or the subject
  is moving may result in grainy images

22
ISO

• ISO is the measurement of the sensitivity of
  the camera image sensor to light.
• An ISO of around 200 is average.

23
ISO

• An ISO of around 200 is average.
• Lower numbers are used when smooth crisp images
  are needed and you have plenty of light.
• Below 200

24
ISO

• An ISO of around 200 is average.
• Lower numbers are used when smooth crisp images
  are needed and you have plenty of light.
• Below 200

25
ISO

• Higher numbers are used in
• limited light conditions,
• Flash is not desirable
• subject is moving
• May result in grainy images

400 and above
26
Choosing ISO Setting
100 to 200 -------Outside Bright
Sun 400----Shade or overcast conditions 400----B
right light indoors 800-1400----Stormy
day 800-1400 Low light indoors
27
Higher ISO400 ISO 800 ISO
Light is limited and flash was not desirable in
either shot.
28
ISO

•   Too little light can leave parts of your
  image too dark to make out details.
• If the ISO had been higher this photograph
  would have been brighter.

Trevi Fountain, Rome ISO 200
29
High ISO

•  
• This photo taken with
• ISO 800. Notice the grainy
• appearance. This is called
• noise.

Rome by night
30
ISO 160

•  
• Notice the camera
• exposes to the light
• not the bride.

More advanced cameras have a mechanism that will
allow you to expose to individual areas with
in the shot.
31
Aperture
32
Aperturef-stops
Aperture is the camera feature that regulates the
amount of light that passes through the lens by
controlling the size of the opening in the lens.
It is measured in f/stops.
33
Aperturef-stops
Aperture is the camera feature that regulates the
amount of light that passes through the lens by
controlling the size of the opening in the lens.
Described as the f/stop the smaller the number
the wider the lens will open
Stopping down
34
Aperturef-stops
The common range for f-stops goes from f/2,
f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22
Narrow depth of field
f/8 is a good average aperture where Most
everything will be in focus.
Infinite depth of field
35
F/stops and depth of field
Lower f stops need less light to expose
Higher f stops need more light to expose
Depth of Field decreases
Depth of Field increases
f/2
F /22
f/8
36
Aperturef-stops
Full f-stops go from f/1.4, f/2, f/2.8,
f/4, f/5.6, f/8, f/11, f/16, f/22,
f/32 Each full stop value increase, decreases
the light entering the camera by half.
Fast lens
Slow lens
Longer shutter speed
Shorter shutter speed
Large depth of field
Narrow depth of field
37
Aperture
Narrower Depth of Field
More exposed
Greater Depth of field
Longer Shutter Speeds
38
Shutter Aperture Relationship
The smaller the aperture, the longer the shutter
speed The larger the aperture, the shorter the
shutter speed.
39
Sunny Sixteen Rule
The "rule of sunny-16" is simply a handy trick to
remember away to set proper exposure when the
sun is high in the sky And casts strong shadow on
a bright day. The camera aperture is set to f/16
(hence the -16 in sunny-16). dark shadows.
The sunny sixteen rule was NOT used in
this photoghraph.
40
Sunny Sixteen Rule
Aperture Stops
Conditions
Aperture stops conditions
f/22 -1 stop snow or beach
f/16 sunny-16 bright daylight dark shadows
f/11 1 stop weak or hazy sun sun low in sky
f/8 2 stops cloudy bright
f/5.6 3 stops darker clouds subject in shadow
f/4 4 stops sunset
41
Issues with each exposure point
ISO
Noise
Changing any of the three elements will effect
the exposure
Shutter Speed
Aperture
Motion Blur
Depth of Field
Aperture and shutter speed are inversely
proportional to each other.
42
Manual Settings Dial
43
Creative Camera Modes
Point and Shoot Modes
Creative modes
44
Program Mode
P
Shutterspeed (exposure) and Aperture are set in
unison automatically. When you change the shutter
speed, the aperture changes automatically When
you change the aperture, the shutter speed
changes automatically
45
Aperture Priority ModeAv
Use Av when Want everything In focus (use high
f/stop) OR Want the background to be out of
Focus (use low f/stop)
In AV mode, the aperture remains constant. By
turning the main dial on your camera, you can
adjust the shutter speed. The aperture remains
the same.
46
Shutter Priority ModeTv
Action shot mode
In Tv mode, the shutter speed remains constant.
By turning the main dial on your camera, you
can adjust the aperture. The shutter speed
remains the same.
47
Manual exposure mode
In M mode, the aperture and the shutter speed can
be altered. By turning the main dial on your
camera, you can adjust the shutter speed. The
aperture remains the same.
Read your camera manual to determin how to set
boththe Av and the Tv
In the Canon Rebel Set the Tv by turning the
dial Set the Av by holding down the Av button and
turning the dial.
48
Manual exposure mode
In the Canon Rebel Set the Tv by turning the
dial Set the Av by holding down the Av button
while turning the dial.
49
Manual exposure mode
In the Canon Rebel Set the Tv by turning the
dial Set the Av by holding down the Av button
while turning the dial.
The standard exposure level is achieved when the
slide bar is located in the center. This meter
may be viewed on the LCD screen or through the
view finder
50
AE LockConsult your camera manual for AE lock
steps
Exposed to a chosen darker subject in the photo
( AE lock)
Exposed to the light (normal )
51
Automatic Depth of Field
Canon's auto depth of field (A-DEP) feature
works by (1) finding the nearest and furthest of
all the autofocus points, (2) setting the
camera's focusing distance to optimally position
the depth of field between these nearest and
furthest points, and (3) setting the aperture so
that the edges of the depth of field extend far
enough to contain these nearest and furthest
points.
52
(No Transcript)