mini-lesson two: aperture

Have you ever noticed that the backgrounds of many portraits and close-up images are out of focus?  This effect is most easily achieved using manual settings of the aperture, but you can get similar results with a point-and-shoot camera without direct control of the aperture.

The aperture indicates the measurement of the lens opening such as f/4 and controls the creative effect of depth of field.  Depth of field refers to the amount of the image that is in focus - in the foreground, middle ground and/or background.

The portraits and close-up images I refer to above have a shallow depth of field which means only a small amount of the image is in focus and the rest of the image is out of focus.  There is a reason why photographers choose to do this, and that reason would be to intentionally blur any distractions and lead the viewer directly to the subject.

Depth of Field (Fig. 1) - Samsung SL605

In this example to the left (Fig. 1), it is difficult to determine which part of the image we should focus on.  What was the photographer seeing when s/he captured this image?  What did s/he want us to see?  The background here is quite busy with a variety of other plants and metal structures, so the eye jumps around the image with no direction.  This photo seems like a simple documentation of the scene that we see - evidence of sorts - as opposed to an image that offers the viewer something below the surface.

Depth of Field (Fig. 2) - Samsung SL605

On the contrary, the image in Fig. 2 places the viewer within the environment of the photograph and gives the viewer a focal point, the cabbage leaf.  The shallow depth of field seen here helps to minimize the distractions that we see in Fig. 1, and the soft focus of the background keeps our eyes focused on the subject.  Note also that the point of view is just slightly lower than that in Fig. 1 which offers the viewer a different perspective and helps create interest.





You can achieve the creative effect of shallow depth of field in a couple of ways.

If you are shooting with a basic point-and-shoot camera without manual controls...

1. Go into the scene modes and choose the close-up or portrait mode - this will cause your camera to use a wide-open aperture setting such as f/2.8 which will allow for a shallow depth of field 
2. Determine your subject and decrease the camera-to-subject distance by physically moving toward it - you must be very close to the subject, around 6-8 inches.
3. Center the subject within the camera frame then swivel to the left or right to compose the image in a balanced way - this is called pre-focus technique.
4. Snap the photo and review the image to check the depth of field - if the results are not apparent, try moving in closer to the subject for a more dramatic effect.

If you are shooting with a basic point-and-shoot camera with manual controls...

1. Set your camera to Aperture Priority indicated by "Tv" and set your aperture to the lowest aperture possible - f/2.8 to f/4
2. Determine your subject and decrease the camera-to-subject distance by physically moving toward it - the closer you are to the subject, the more exaggerated the effect.
3. Center the subject within the camera frame then swivel to the left or right to compose the image in a balanced way - this is called pre-focus technique.
4. Snap the photo and review the image to check the depth of field.

Practice using the creative effect of depth of field with inanimate subjects in the beginning and be sure to write down the steps that you take so that you can recreate successful images.  Lastly, remember to find me on Flickr - msabbydw - and join our photo group, church of photography, to share your images for praise and constructive feedback!