Digital
Photography I
Aperture
ISO
Shutter Speed
The
Exposure
Triangle
Digital Photography I
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.
Exposure
Exposure is the total amount of light
that you allow into the camera
Exposure Triangle
ISO
Changing any of the
three elements will
effect the exposure
Aperture
Shutter
Speed
Aperture and shutter speed are inversely proportional to each other.
Exposure Triangle
http://www.flickr.com/photos/robert_d_ellis/5387408926/
Camera Configuration
Digital Sensor
Shutter
Aperture
Lens
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.
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Exposure
Too little light results in an
under-exposed image where
there are areas of low detail.
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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
Shutter
Speed
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
Shutter Speed
• Shutter Speed—the amount of time the shutter is open—
which 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.
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Shutter Speed
Action shots require fast shutter speeds.
Callaway Gardens
Steeple Chase
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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.
15
Low Light
requires longer shutter speeds and a tripod
Full 1 second shutter speed
Langdale Mill
Low Light
requires longer shutter speeds and a tripod
Shutter Speed
Must use
A tripod
Best for
Sports
shots
ISO
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
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The Exposure Triangle
ISO – International Organization of Standardization
ISO—the 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
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ISO
ISO is the measurement of the sensitivity
of the camera image sensor to light.
An ISO of around 200 is average.
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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
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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
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ISO
Higher numbers are used in
• limited light conditions,
• Flash is not desirable
• subject is moving
• May result in grainy images
400 and above
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Choosing ISO Setting
100 to 200 -------Outside Bright Sun
400----Shade or overcast conditions
400----Bright light indoors
800-1400----Stormy day
800-1400 – Low light indoors
Higher ISO
400 ISO
800 ISO
Light is limited and flash was not desirable in either shot.
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
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High ISO
This photo taken with
ISO 800. Notice the grainy
appearance. This is called
noise.
Rome by night
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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.
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Aperture
Aperture
f-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.
Aperture
f-stops
Described as the f/stop
the smaller the number
the wider the lens will open
Stopping down
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.
Aperture
f-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
F/stops and depth of field
Lower f stops need less light to expose
f/2
Higher f stops need more light to expose
Depth of Field
decreases
f/8
Depth of Field
increases
F /22
Aperture
f-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
Shorter shutter speed
Narrow depth of field
Slow lens
Longer shutter speed
Large depth of field
Narrower Depth of Field
More exposed
Longer Shutter Speeds
Greater Depth of field
Aperture
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Shutter Aperture Relationship
The smaller the aperture, the
longer the shutter speed
The larger the aperture, the
shorter the shutter speed.
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.
Sunny Sixteen Rule
Aperture
Aperture
f/22
Stops
stops
-1 stop
Conditions
conditions
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
Issues with each exposure point
ISO
Noise
Changing any of the
three elements will
effect the exposure
Aperture
Shutter
Speed
Motion Blur
Depth of Field
Aperture and shutter speed are inversely proportional to each other.
Manual Settings Dial
Creative Camera Modes
Point and Shoot Modes
Creative modes
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
Aperture Priority Mode
Av
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.
Shutter Priority Mode
Tv
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.
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.
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.
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
AE Lock
Consult your camera manual for AE lock steps
Exposed to the light (normal )
Exposed to a chosen darker subject
in the photo ( AE lock)
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.