Focus and Camera Stability

Autofocus is important for determining which part of the scene is in focus and which parts are blurry. When you have a basic understanding of how your camera's autofocus system works, you need to develop good habits for keeping the entire camera steady while shooting. Otherwise, the entire scene will be blurry and nothing will be in focus; not even the wall in the background. In short, autofocus does nothing to compensate for camera shake.

Although most of us do our best to keep things steady while shooting, there are pitfalls to be aware of. The first is when you're shooting in low light. In dimly lit situations, you must open up your camera's aperture to let in more light. You must also slow down the camera's shutter speed so that more light can pass through the lens. If you're shooting in automatic mode, the shutter speed is automatically lowered, making the long exposure far more sensitive to any movement. In addition, the slightest finger movement while pressing the shutter is more than enough to blur the image. Although some manufacturers have developed cameras and lenses that nullify a small degree of camera shake, it's still a good idea to use a tripod for any shots below 1/30 of a second (see Chapter 2, "Digital Exposure," for more on the relationship between shutter speed and f-stops).

If your subject is moving along a predictable path, you can pan the camera to follow the movement. Doing so blurs the background even more, while keeping the moving subject in sharper focus. For example, if you're shooting a horse race or stock car race, pan the camera to follow the subject, and the results will be sharper.

 Shed
Nikon D2H
1/100 sec, f/9
Focal length 12mm

 Shed Detail
Nikon D2H
1/125 sec, f/17
Focal length 22mm

Timing

There's more to focus than simply mastering the autofocus feature and holding the camera steady. These technical skills will make certain image areas sharp, but a better question to consider is what to shoot at, or perhaps when to shoot. These questions revolve around the photographer's goal of capturing the decisive moment.

TECHnote: Improving Focus in Photoshop

The Unsharp Mask dialog box.

The first thing to keep in mind is that sharpening in Photoshop is no replacement for getting the focus right in the camera. Repeat after me: Sharpening is not focusing. Your camera is capable of making judgments about the distance of the subject to the camera, and where one object ends and another begins. Because this 3D thinking isn't possible for Photoshop, the program treats the image as a flat 2D grid of pixels, unless you manually define the objects and relative distances.

On the other hand, if you're just trying to give the edges in your subject a boost, Photoshop's Unsharp Mask filter is a great tool. Follow these steps to get the best results from Photoshop's Unsharp Mask filter:

Output Resolution. Set the size of the image before you scale it up or down. Setting the sharpness and then reducing the image is likely to erase the detail you just created.

Bicubic Sharper or Smoother. When scaling the image up or down, make sure that you use the correct interpolation setting. Use Bicubic Sharper when making the image smaller to maintain image detail. Use Bicubic Smoother when making the image larger to smooth the effects of pixilation. These settings can be found in the Image Size dialog box, after enabling the Resample Image option.

View Actual Pixels. When sharpening, make sure you're viewing the image at a 1:1 pixel ratio by selecting View, Actual Pixels.

Amount versus Radius. Set the ratio of the Amount and Radius sliders in the Unsharp Mask dialog box depending on the image being sharpened. For images with lots of detail, set the radius below 1 pixel and use a higher Amount setting. For softer images where you want to sharpen only major contrast areas, set the Radius higher and the Amount lower.

The best way to capture the moment is to have an innate sense of intuition and timing. Unfortunately, these skills are largely instinctive and are developed more through experience than instruction. Having said that, using your camera's burst exposure setting is extremely helpful in capturing a number of shots in a brief time span, increasing your chances of nailing the decisive shot.

Whether you're shooting in single or burst (multi-frame) mode, it's important to get used to the shutter lag that happens between the time you push the shutter release and the moment the image is captured. When you press the shutter release, the camera determines exposure, sets white balance, and focuses on the subject. On some cameras, this set-up time creates a noticeable delay before the picture is taken. Sometimes you must adjust your timing to get the shot right. In certain cameras, it's possible to switch from active to passive focus mode, eliminating the pre-focusing beam that can create the shutter lag. Each camera is different though, so check your owner's manual and practice to understand the specifics of your system.