CS 39J
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Schedule & Notes
> Session 7 Detailed Notes
Computer Science 39J
March 7, 2008
Notes
Photos – visually
Reciprocity failure
When you have photos looking different between long exposures and shorter exposures
Long exposures
are a summation of the light present
Normally you can change f-stops and shutter speed to make up for light, etc., but with long exposures, the trade-offs don’t hold
More reading:
http://en.wikipedia.org/wiki
/Reciprocity_failure
Texture and lighting
:
Light highly affects texture, accentuates it
The term “
very hot
” is used to describe a glare
Very bright, hard to hold detail or texture on the subject due to strong light, flash, etc.
Parts of the image gets washed out
Dynamic Range
:
The difference between the brightest and darkest spots of a photo
Solutions
to high dynamic range
Graduated
ND
filters
for lenses
In the darkroom:
dodging
techniques
Underexposing:
If you take a picture underexposed during dusk, it can look like a more detailed night scene
Underexposing in color can also create more vivid shots
Slide film (color reversal film)
: the film is slightly underexposed and thus the colors come out more vivid
Ongoing debate:
Is richer and more vivid color, unnaturally made, “better?”
What do we mean by “better?”
How we see:
The
human visual system
is different from projectors, monitors, cameras, paper, etc.
We have
vision devices
to compensate for light
Two things happen
to our eyes when going from light -> dark
Pupils dilate
Sensitivity of rods and cones shift
Slide film
Changes color response to film
Provides a more saturated color, as mentioned above
We will probably use slide film as the assignment for Spring Break
Potential spring break assignment
Different
types of slide film/color reversal
film
Fuji
Velvia
Provia
Kodak
Extachrome
VS…(very saturated…)
Assignment
Portraits!
Take
two
shots
One
candid
portrait of a subject
One
posed
portrait of a subject