In the previous few articles, I have discussed some basic aspects of photography. The first subject to get a close look was exposure, and I have discussed two of the three components that control it: shutter speed and aperture. In this article, I will bring in the missing piece - ISO (or film sensitivity). After that I will conclude the exposure subject.
We have learned that the sensor (or film) can get the same exposure if we prolong the duration the shutter is open, but use smaller aperture (or shorten the duration that the shutter is open, while using a bigger aperture). If we want to be absolutely honest (which, at least for now, we do), we have to include the third part of the equation: film sensitivity (AKA ISO).
In short - ISO sets the impact that light will have on the sensor. High ISO will make our exposure brighter, while low ISO will make our exposure darker.
So how can we use ISO to produce better photographs? Click to continue ›