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• Exposure
• Depth of Field
Basics of Exposure
• ISO
• Ratio Lighting
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Exposure
Time = Shutter
• The length of time your aperture is open for
• The larger the number the faster your
aperture will open and close.
• You are in charge of the light!
• The two main controls – shutter and aperture
– How long you let the light in
• 1000 of a second is faster than 60th of a
second
– How much light you let in
• Time & Intensity
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• Shutter speeds tend to double
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Time = Motion
• Fast shutter speed
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• Slow shutter speed
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Latency
• in film photography, the invisible configuration
of silver halide crystals on a piece of film after
exposure to image-bearing focused light seen
upon processing
• Digital – the ability of the light to keep
building up continuously as long as the lens is
open
– The buffer keeps over writing itself
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Intensity
Focal Length?
• Aperture
• Controls how much light is
let in for a specified time
• The distance from the lens to the film, when
focused on a subject at infinity
• Affect depth
• Referred to as an F-stop
• The ratio is between the diameter of the
aperture in the lens and the focal length of
the lens.
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Standard F-stops – Full Stops
Aperture Controls Depth
• The smaller the aperture, the deeper the
depth
• The wider the aperture, the shallower the
depth
• F2 is a large aperture
• F32 is a small aperture
• Got it?
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Depth of What?
Can be a useful tool
• Depth of field
• Depth of field refers to the range of distance
that appears acceptably sharp
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm
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Tells the viewer what you want them
to look at
Rules of Depth
• Isolates an object in the frame
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• The shorter your focal length, the smaller the
aperture, the greater the depth
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Reciprocity
The relationship between
intensity and time
• The longer the focal length, the larger the
aperture, the shallower the depth of field
Each variable affects another variable
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ISO
• In digital it is matter of amplification
– how much amplification is applied to the signal from
the image sensor.
• Increased chip voltage needed to compensate for
light variance
• The smaller the photo pitch (photosite size)
– The more noise is created a higher amplification
– (less efficient signal to noise ratio
• That is why small point and shoots are so noisy!
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Typical ISO Numbers
Affects Exposure
• 100, 200, 400, 800, 1600..ect
• Since most cameras base calibration is at 100,
the higher you go , the noisier the chip
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Review of Aperture/Shutter/ISO
Ratio Lighting
• The term "lighting ratio" is a quantitative
measure of the difference between two light
sources
• A 1:5 ratio would mean that one side of the
object would be 5 times as bright as the
other
• https://youtu.be/6-NhJua5NFA
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1:1 Ratio
Ratio is controlled by Light
Rembrandt Understood That
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