Aperture, the size of the hole letting light through your lens, is the third variable you control to get properly exposed photos. Last October I discussed ISO, the sensitivity of your camera’s digital sensor. In November I wrote about shutter speed and how your choice is a creative one as well as an exposure control.
Like shutter speed, the aperture you choose affects the “look” of your photo as well as the exposure so it’s both a creative and technical choice. The family portrait above was made at a middle aperture to balance depth of field and shutter speed with proper exposure.
You can think of the aperture as the size of the “light pipe” carrying photons through your lens. The larger the diameter of the pipe, the more photons go through, just as a 2” water pipe carries more than a ½” pipe. Continue reading