Thursday, August 26, 2010

Aperture

Aperture - Defined by Wikipedia as... "In optics, an aperture is a hole or an opening through which light travels."

In a camera, the aperture is the opening of the lens. The lens of a camera can be compared to our eyes... On a bright sunny day, our pupils will get very small only allowing a limited amount of light to enter. In the dark our pupils open wide, letting in more light, which helps us to see better.

In photography the aperture is used to control light exposure and depth of field. You can change the aperture to allow for a longer or shorter depth of field.

When photographing landscapes or wide angle shots a narrow aperture will allow for more depth of field so the entire scene can be in focus from the flowers in the foreground to as far as the eye can see.

Narrow Aperture f/29
(the foreground and the background are in focus)

For portraits or photographing small objects a wide aperture will shorten the depth of field allowing your subject to be sharp but blurring the background for less distraction.

Wide Aperture f/4.5
(the subject is in focus and the background is blurred)

The aperture of a camera is measured in "f-stops" (i.e. f/2.8, f/4.0, f/5.6, f/8.0, f/11, f/16, f/22). The smaller the aperture number or f-stop the wider the aperture opening.

Below are a couple more examples of how aperture numbers affect depth of field in a photograph. The exercise on aperture in my first DSLR lesson was to arrange several same size objects evenly spaced away from the camera lens. For both sets of images I took one photo on each of the aperture settings. I put 4 of each together to show the aperture range.

Click on the images for better resolution and more detail.
 Top, Left - f/4.5, Top, Right - f/7.1
Bottom, Left -  f/14, Bottom, Right - f/25

Top, Left - f/4.0, Top, Right - f/7.1
Bottom, Left -  f/11, Bottom, Right - f/25

For both sets of images... The first image (top, left) is a wide aperture, creating a shorter depth of field (see how the the objects in the foreground and further in the background are out of focus?). With the last image (bottom, right) a narrow aperture opening was set for more depth of field (the larger focal plane allows for more clarity on objects near and far).

Next lesson... Shutter Speed here I come.

1 comment:

Lenore @ Lather. Write. Repeat. said...

Great job Jenny, reads very well! ;)

XO
Lenore

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