Know your stuff
Select the correct auto focus (AF) area to capture pin-sharp images when shooting action sports
Trying to keep a moving target under a single AF point – when it’s hard enough just to keep it in frame – is almost impossible and pretty impractical. Luckily our cameras have different AF points and these can be combined in different ways to suit every situation. From a single AF point through to full auto, the maps differ greatly. How to do it Go into your menu (or press your AF selector button) and find the AF Area selection panel to select and change your AF area. The maps will combine five, nine or all AF points (Auto) and a couple of variants in between, depending on your model of camera.
For best results with moving subjects, use one of the larger AF area settings, like Zone AF. These will give you a bit of leeway for framing your image. You can move these around the viewfinder, and they cover a big enough area to keep your moving subject covered when tracking. If you find your AF constantly jumping between background and foreground, try a smaller AF area while keeping the activated AF points over the subject.
Full auto works when the subject has a clean background, like the sky or one that’s very out of focus. But it will struggle to focus on a single subject when shooting against a background with details that it can latch onto.
THE HUMBLE SHUTTER – WHAT DOES IT DO?
That iconic ‘click-clack’ you hear as you press the shutter button is not actually the shutter but the sound of the mirror going up and down. Ironically, even though it’s called shutter noise, the shutter barely makes a sound except for a very faint clicking. At fast shutter speeds and large apertures, the shutter tends to create a bit of vignetting (darkening of the corners of the image), but not always.
There are three main types of shutters and all of them do exactly the same thing, but in very different ways: expose the sensor/film plane to light for an exact amount of time, hence shutter speed. Leaf shutters Found in compacts and medium-format cameras. These are built into the lens and are shaped like an iris that opens and snaps shut.
Focal-plane shutters Found mostly in SLR and DSLR cameras. The shutter consists of two curtains that move across the sensor. The first curtain opens the sensor to light and the second blocks off the light. The faster the shutter speed, the smaller the gap between the first and second curtain. When using flash, this can become visible if you shoot at a fast shutter speed (over 1/160 sec).
Digital shutters Mostly used on mirrorless cameras.
These don’t have any moving parts. This has its limitations because the CMOS (card reader) can’t read the information all at once but one row at a time. This has the effect of reducing shutter speed
– an issue for photographers working in 1/100 and 1/1 000 secs.
ZONE AUTO FOCUS