Friends and family have asked me to explain the basics of photography to them in layman’s terms. There is a lot of technical terminology that goes along with an endless variety of equipment choices, and the learning curve appears steep. Here is a simple comparison that should help make the ascent a little easier.
Think of your camera as your eye.
Imagine you walk to the kitchen for a midnight snack. Even though the house is dark, your eyes are adapted to the dark and it seems easy to find your way. When you open the refrigerator, you are suddenly blinded by the bright white light beaming back at you.
Your eyes squint to protect themselves from the change in light. You find your cake and close the fridge, and your eyes take a few moments to adjust back to the wide open state they were in on your way to the kitchen.
To sum up your midnight adventure, with your eyes wide open, you could see in the dark to find your way. When you opened the fridge door you couldn’t see anything. You had to adjust your eyes by squinting or everything would be washed out with too much light.
In camera terms, squinting would be using a small aperture. The aperture is the size of the opening in your lens, and its value is measured as an “f-stop” or f#. Confusingly, f22 is a small opening and f2 is a large opening. F2 would be like your eyes adjusted wide open on your way to the kitchen, and f22 is what your eyes would be when staring into the refrigerator.
Looking at a bright light for too long hurts, right? In camera-speak, the function controlling this is the shutter speed. When it’s bright out, you usually use a small aperture (lens opening) with a short duration shutter speed (1/500th second or less). Both of these factors limit the time your camera’s sensor is recording light.
Generally, when shooting in a bright light, use a small aperture (high f-stop) and a fast shutter (1/500th of a second or less.) In low light, use a large aperture (small f-stop) and slow shutter. Take many photos, and experiment with both variables. Properly balanced, the image that appears will have a balanced range of tones.
These are very general examples and advice. But for the most part your eyes behave very much like the aperture on your lens. By thinking of shutter speed as how long we expose our eyes to the light we’re letting in, we get a good idea of how an image is made.
I will explain how your eyes or lens affect the depth of field in another post. I hope this advice helps. Now I have to go stumble into the kitchen for that piece of cake.