SLIDE 1
The Art, Science and Algorithms
- f Photography!
Camera Capture & White Balance! CSCI 4900/6900! Maria Hybinette!
1!
Recap!
- Exposure!
– Control:!
- Shutter, aperture and ISO!
– Metering!
- Camera meter!
- Histograms!
- Zone system!
– Limitations:!
- Your meter knows about ‘middle gray’!
- Limited dynamic range (contrast levels)!
2!
Basic Photography: Left to talk about!
- Digital Capture:!
– Bits / RAW and dynamic range!
- HDR (beginning, Photoshop)!
- White balance (start tomorrow)!
- Gamma (Thursday)!
– http://graphics.stanford.edu/courses/cs178/applets/ gamma.html!
Coming Soon:!
- Camera hacking (next week)!
- Noise and dynamic range!
- Advanced HDR!
- Lenses, focal lengths, distortion and DOF !
3!
Digital Camera: Linear Capture!
- Film record light in a non-linear
fashion, just like our eyes.!
– It enables us a higher dynamic range, we can naturally compress contrast levels.!
- Doubling number of photons reaching our eyes
doesn’t seem twice as bright.!
- Digital sensors lack the non-linearity of
human perception!
– Count photons in a linear fashion!
4!
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Digital Exposure Dangers!
- Expose it assuming film (non-linearity)!
- Don’t exploit camera’s true dynamic range!
- Create exposure whose shadows are noisier than then
should be!
- Non-linearity: Real life examples:!
– Golf ball in hand and weight! – If you add another golf ball does it feel twice as heavy? [probably not]! – If you add twice the number of photons reaching your eye does it feel twice as bright? !
- Brighter yes – but TWICE as bright? Probably not.!
5!
Linear Capture!
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