Exposure

Combination

with DSLR



EQUIVALENT EXPOSURE COMBINATION


ISO: 100*2^n

Aperture: sqrt((1/2)^n)

Shutter Speed: (1/2)^n


Equivalent on Exposure Value




Equivalent exposure combination


Accurate Exposure

ISO 100 

f 1.8 + 1/500 
= f 4 + 1/125 
= f 8 + 1/40


Aperture


AP: Aperture Priority

Depth of Field

  • Aperture
  • Focal Length
  • Distance


Common Aperture Value


  • Macro photography: 1:1, f11 ~ f1
  • Creative shooting: Bokeh f/1.4 ~ f/2.8
  • Sports: f/2.8
  • Indoor portrait: Single f/2.8 ~ f/4, Multiple f/5.6 ~ f/8
  • Outdoor portrait: f/2.0 ~ f/5.6
  • Landscape photography: f/11 ~ f/22


ISO


  • CCD: Charge-coupled device
  • CMOS: Complementary metal–oxide–semiconductor

So = A (Si + n)
A <==> ISO 





Dynamic Range


Film: EV ± 9
Digital: << EV 9

Linear Range of sensor

HDRI:High Dynamic Range Image

Multixposure + Image Merge



Sampling


sRGB, adobeRGB: 8 bit

RAW: 10 ~ 12 bit

NOISE


SNR = Si / n

n = n(light) + n(circuit) 

Si ~ Luminous  Intensity   
n(light) ~ Luminous  Intensity  
n(circuit) ~ relatively constant


ISO  amplifies the signal but doesn't improve SNR



Shutter Speed


SP/TP: Shutter Priority/Shutter Priority

Max Speed: Mechanical Restriction

Bulb: B Shutter


Noise


Accumulation Effect

Lo = [Ii + n(circuit)] * t

Ii = Iis + n(optical)

SNR = Iis  / n
n = n(circuit) + n(optical)

t increase the light intensity but won't improve SNR


Two Limitation



Noise
Dynamic Range
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