Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16PhotonrateTimeEnd of exposureEnd of exposureIdealRate of incoming light is constantReal lifeRate of incoming light is fluctuatingPhotonrateTimeHow much fluctuation?√nDictated by Poisson (pwasõ) DistributionFor n total photons in exposure,standard deviation =Photons collected = n + √nIf n = 10,000 photons,Photons collected = 10,000 + √10,000 = 10,000 + 100 photons√n, so what?Variable brightness = noise!Noise monsterOne of the photographer’s worst enemiesProportion of Photon Fluctuation (√(n)/n)PhotonsProportion of Photon Fluctuation (√(n)/n)PhotonsProportion of Photon Fluctuation (√(n)/n)PhotonsProportion of Photon Fluctuation (√(n)/n)PhotonsProportion of Photon Fluctuation (√(n)/n)PhotonsCanon A570IS7.1 Megapixels1/2.5” sensor5.76 x 4.29mm (24.7mm2)Density: 3.48 μm2/pixelISO100 ISO200 ISO400ISO800 ISO1600Canon A570IS7.1 Megapixels1/2.5” sensor5.74 x 4.3mm (24.7mm2)Density: 3.48 μm2/pixel1002004008001600images: dcresource.comISO100 ISO200 ISO400ISO800 ISO1600Fuji F306.1 Megapixels1/1.7” sensor7.7 x 5.77mm (44.4mm2)Density: 7.27 μm2/pixel1002004008001600images: dcresource.comISO100 ISO200 ISO400ISO800 ISO1600Canon 30D8.2 MegapixelsAPS-C sensor22.5 x 15mm (337.5mm2)Density: 41.16 μm2/pixel1002004008001600images: dcresource.com30D30DF30F30A570ISA570IS8.2 Megapixels22.5 x 15mm (337.5mm2)Density: 41.16 μm2/pixel6.1 Megapixels7.7 x 5.77mm (44.4mm2)Density: 7.27 μm2/pixel7.1 Megapixels5.76 x 4.29mm (24.7mm2)Density: 3.48 μm2/pixelProportion of Photon Fluctuation (√(n)/n)ISOMaking matters worse, circuitry must occupy some space between each photowell – the more photowells, the more space circuitry takes up.SummaryMore pixels, smaller sensor => less light per pixel => more noiseLess pixels, bigger sensor => more light per pixels => less noiseIn theory, the biggest sensor with the least pixels will give us the best image, in terms of noise.A 1-pixel sensor would be ideal. With 1 pixel, we’d have low noise but no detail.Many pixels => High detail, high noiseFew pixels => Low detail, low noiseThe “Megapixel Myth”: Detail vs. NoiseMegapixels: Detail vs. NoiseFacebook profile picture: 4x6 studio print at 300dpi: 5x7 studio print at 300dpiStandard VGA TV: 1080p HDTV: 1280x1024 19” LCD monitor: 8.5x11in, 300dpi magazine spread:8x10 inkjetprint at 200dpi:10x14in, 150dpi full-page spread in Daily Cal: Giant 20x30in poster print at 150dpi:0.03 MP2.16 MP3.15 MP0.35 MP2.07 MP1.31 MP8.42 MP3.20 MP3.15 MP13.5 MPHow many pixels do we need?:If you only look at pictures on the computer, 2-3MPIf you make non-poster-size prints (4x6, 5x7, 8x10), 3-4MPMore pixels beyond this don’t add detail, and contribute to greater