# Exposure

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```					                             Exposure Triangle

Exposure = Aperture + Shutter Speed + ISO

WINDOW ANALOGY

Aperture = size of the window, itself, and how much light it lets in
The aperture is the opening through which light passes when a photo is
snapped on a camera.

Shutter Speed = how long shutters are open on window, affecting how
much light gets in

ISO = how the room behind the window is affected by the amount of light
being let in through the window

APERATURE
*size of opening in lens when picture is taken
*is measured in F-stops
*also compared to human pupil/in the dark pupil is as large as 8 mm
(f/2.1)/in the light pupil is as small as 2mm (f/8.3) to control how much light
the eye allows in for visual processing/average pupil is 4 mm
*indicated as “A” or “Av” on your camera settings dial
*most important setting to master for creative photography

Small Aperture (large F-stop#)      Large Aperture (small F-stop#)
light     little light enters camera           lots of light enters camera
allows more things in picture to     causes vignette effect, can distort
DOF       remain in focus at various           subject
distances
DOF       greater depth of field (DOF)         decreases depth of field (DOF)
Shutter   goes with faster shutter speed       goes with slower shutter speed
Cost      easily done with smaller pocket-     usually achieved only with heavier,
sized cameras                        more expensive equipment
Exposure Triangle
f/32 (small aperture + slow shutter speed)

f/5.6 (large aperture + fast shutter speed)
Exposure Triangle

SHUTTER SPEED
*the amount of time the shutter is open when a photo is snapped
*indicated as “S” or “Tv” on camera settings dial
*measured in seconds, 1/1000 is much faster than 1/30
*usual is 1/60 or faster, slower causes blur due to camera movement while
shutter is open
*use tripod for slower than 1/60
“Bulb” mode or “B” mode allows shutter to remain open
*main question to ask is “Is something in the scene moving?”
1. to freeze or still the motion, cleaner details, choose faster shutter
speed
2. to capture the motion as an intentional blur, choose slower shutter
speed
3. how fast or slow to set it depend upon how much blur you want and
on how fast the subject is moving
*general numbers and setting rule = keep number of shutter speed
denominator larger than number of focal length of the lens
Exposure Triangle

Slow Shutter Speed             Medium Shutter Speed

Fast Shutter Speed
Exposure Triangle

ISO
*low number = low sensitivity = finer pictures
*high number = high sensitivity = grainier pictures
*use high ISO in darker situations that need fast shutter speeds / ex…
indoor sports shot
*100 ISO is usual setting for clean, crisp pictures / low noise (grain)
*use faster shutter speed with higher ISO setting
*4 main questions to answer before setting ISO
1. light – is subject well lit?
2. moving subject – is subject moving or sitting still?
3. tripod – do I have a tripod?
4. grain – do I want shot to be clear or grainy?

good light + stationary subject + tripod + want no grain = low ISO
low light + moving subject + no tripod + want grain/noise = higher ISO

*situation when you might need higher ISO settings
1. indoor sports events = subject is moving + light is limited
2. concerts = low light setting + “no flash allowed” areas
3. art galleries = “no flash allowed” areas
4. parties with candles = auto flash would ruin the shot
Read more at http://digital-photography-school.com/iso-
settings#ixzz1rIcvDsZB
Exposure Triangle
100 ISO

3200 ISO

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 views: 9 posted: 8/17/2012 language: English pages: 6