title: Pixel per square foot
body: <p>I was reading about pixel per foot but can someone teach how can i calculate the pixel per foot?
  If given the resolution 640(horizontal) x 480(vertical), lens range from 2.8 mm - 12 mm, distance = 16ft (around 5 meter) and pixel per foot equals to?</p>
  
  <p>Anyone?</p>