CS 39J > Schedule & Notes > Session 7 Detailed Notes

Computer Science 39J

March 7, 2008

Notes

    1. Reciprocity failure
      1. When you have photos looking different between long exposures and shorter exposures
        1. Long exposures are a summation of the light present
      2. 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
      3. More reading: http://en.wikipedia.org/wiki/Reciprocity_failure
    1. Texture and lighting:
      1. Light highly affects texture, accentuates it
      2. The term “very hot” is used to describe a glare
        1. Very bright, hard to hold detail or texture on the subject due to strong light, flash, etc.
        2. Parts of the image gets washed out
      3. Dynamic Range:
        1. The difference between the brightest and darkest spots of a photo
    2. Solutions to high dynamic range
      1. Graduated ND filters for lenses
      2. In the darkroom: dodging techniques
      3. Underexposing:
        1. If you take a picture underexposed during dusk, it can look like a more detailed night scene
        2. Underexposing in color can also create more vivid shots
        3. Slide film (color reversal film): the film is slightly underexposed and thus the colors come out more vivid
          1. Ongoing debate: Is richer and more vivid color, unnaturally made, “better?”
            1. What do we mean by “better?”
    1. The human visual system is different from projectors, monitors, cameras, paper, etc.
    1. We have vision devices to compensate for light
      1. Two things happen to our eyes when going from light -> dark
        1. Pupils dilate
        2. Sensitivity of rods and cones shift
    1. Changes color response to film
      1. Provides a more saturated color, as mentioned above
      2. We will probably use slide film as the assignment for Spring Break
      3. Potential spring break assignment
      4. Different types of slide film/color reversal film
        1. Fuji
          1. Velvia
          2. Provia
        2. Kodak
          1. Extachrome
          2. VS…(very saturated…)
    1. Portraits!
      1. Take two shots
        1. One candid portrait of a subject
        2. One posed portrait of a subject