Focusing issues

Viewfinder focusing areas - In the viewfinder of a modern AF system you will see at least one, but probably more than one, focusing area. For the camera to focus accurately, the subject must be in this area. In entry-level cameras the area is positioned in the center of the frame. In the viewfinders of more expensive examples you will not only find multiple focusing areas but you will also notice that they are distributed across the viewfinder. With the aid of a dial, or a thumb toggle, the photographer can choose which area will be used for primary focus. This enables the focusing of subjects that are off center. Zone focusing - There are a range of activities that allow the photographer the chance to predict where the subject will be with reasonable accuracy. In swimming, for instance, the lanes and the end points of the pool are well defined. To use this technique the photographer would pre-focus (in manual mode) on one point in the pool and wait for the subject to pass into this zone before pressing the shutter.

Single and constant auto-focus - In AF terms these two modes determine the way in which the auto-focus system works on your camera. In single mode when the button is held halfway down the lens focuses on the main subject. If the user wishes to change the point of focus then they will need to remove their finger and repress the button. If the subject moves whilst using this mode, then you must refocus.

The constant or continuous focusing mode also focuses on the subject when the shutter button is half pressed, but unlike the single mode, when the subject moves the camera will adjust the focusing in order to keep the subject sharp. This is sometimes called focus tracking. Some AF systems have taken this idea so far that they have 'pre-emptive focusing' features that not only track the subject but analyze its movement across the frame and try to predict where it will move to. This in turn helps to keep the main subject fully sharp.

Get Paid to Take Digital Photos

Get Paid to Take Digital Photos

Reasonable care has been taken to ensure that the information presented in this book isĀ  accurate. However, the reader should understand that the information provided does not constitute legal, medical or professional advice of any kind.

Get My Free Ebook

Post a comment