Fundamentals of Photography Science
Exposure Value (EV)
Rated in “Stops” indicates the amount of light striking the film or sensors. Each stop value is an increase of double or decrease by ½ of the amount of light creating the image. Over all the EV is a function Aperture size, Shutter Speed and Film Speed or Sensor Sensitivity.
Film Speed
Fast film or sensors indicates how long of an exposure is required to produce the image on the film, The actual film or sensor speed is given by the International Standards Organization (ISO) number. The standard ISO numbers are 50,100,200,400,800,1600&3200. The higher the number the higher the sensitivity. With an increase in sensitivity the noise or grain becomes more pronounced.
