Using Aperture: Creative Power with Your Camera’s F-Stop
by Gwyn Calvetti (Apr 4, 2005)
If you’ve owned an SLR (single lens reflex) camera for a while and have yet to take it off the “auto” setting, you’re missing a tool that will allow for creative shooting and control over your final image: the aperture setting, also known as “f-stop.”
To understand the potential behind its use, you first need to understand what is meant by “depth of field,” which is affected by your choice of aperture. Depth of field refers to the area in a photo that is in sharp focus. This area can be increased or decreased by careful aperture selection when you make your exposure.
How do you know whether your chosen aperture will give you a shallow or long depth of field? The numbers tell the story. If the number is large, the depth of field will be long. If the number is small, you’ll have a shallow area of focus. An aperture setting of f/22 will provide a sharper overall image than one of f/4.
Aperture for Creative Control
The other way to control for aperture is to use the full manual setting usually labeled “M”. This setting allows you to choose both your shutter speed and the aperture, achieving a balance between shutter speed and depth of field that best suits your shooting needs. Your camera guide can give you specific details about each setting on your exposure control dial.
Aperture Cleans up the Clutter
Take a look at the two examples shown here. One was shot with a small f/stop of 32, the other with a wide open f/stop of 4.0. You can see how this simple tool right on your camera can replace weekly housework, at least in your photos!
Tip: If you are taking photos of family, friends or pets with a wide-open aperture, make sure their eyes are your point of focus. As long as the eyes are clearly focused, any softness about the edges will be largely unnoticed.
Aperture Brings It All into Focus
Regardless of the depth of field, every image has a focus point where the final image is the sharpest and clearest. When focusing on your subject, keep in mind the point at which you want your sharpest focus and use that as your focusing point (such as a person’s eyes). Study the examples shown here. The first set was shot with a shallow depth of field at an f-stop of 5.0. Each picture uses a different focus point. The second set of photographs was shot with a larger depth of field at an f-stop of 22, again using different focus points. You can see here the difference your focusing point and depth of field can make on the final image.
A Few More Tips and an Aperture Trick
If you use the macro setting—the little flower on the dial—it will result in a very shallow depth of field. Although this can be an advantage in shooting close-ups of things like flowers, you need to accept that part of the image will have a bit of soft focus. A trick I learned for this type of shooting involves using the telephoto lens instead. If you can step back far enough to zoom in on your intended subject with a wide aperture of f/5.6 or larger, you can isolate your subject, blur the background and still have a crisp image. The wildflower photo was shot in this manner, allowing sharper focus of the entire plant.
Try It Yourself