I’m currently in the last 48 hours of my first ever visit to the Grand Canyon in Arizona. Just hours before setting out to see the Canyon for the first time, I realized that I couldn’t recharge my camera’s battery. I had 80% of a full charge, and four more days of vacation to go. Time to panic?
In a previous article we looked at how lenses work. We learned about the focal length. Today we’ll focus on camera lenses and what the term f-stop means.
The term f-stop is a ratio. It has no dimensions. You don’t measure an f-stop in meters, inches, kilograms or even degrees Fahrenheit. An f-stop is the ratio of two distances. It’s the ratio of the focal length of a lens to its diameter. In figure 1, the f-stop is f/d _where _f is the focal length and _d _is the diameter.
This is the first in a series of blog entries on photography. Today we look at one of the most critical parts of any camera - the lens.
Have you ever noticed that people can run faster on flat ground than on sand or water? It’s the same way with light. Light travels faster in air than in glass.