What is aperture?

An aperture is the opening of a lens that allows light to reach a digital camera’s sensor, where light is received by the camera.

The smaller the f/stop number, the larger the opening.

You will see the increments on the lens, or if a lens does not have increments, you can change them on a dial on the camera.

Every increment is called an f/stop (or stop, for short). Though there are smaller increments, such as 1/2 or 1/3 of a stop.

If you have the camera set on automatic, the camera will decide the aperture. Switch the camera to either Aperture Priority mode or Manual mode to select the aperture you want.

The wider the aperture, the more out of focus the background (or if you wish, foreground) will be.

Wide angle lenses, or those without telephoto strength (or magnification), do not provide as much out-of-focus effect.

The out-of-focus effect is called “bokeh.”

An advantage of using a wide aperture is that shutter speeds are faster, which is good for action photography.

Macro (close-up) photography is also a good time to use strong bokeh. Small subjects such as flowers, toys, and bugs stand out better with an out-of-focus background.