Almost all modern cameras have an auto focus mechanism in them. This function can be very useful in standard light conditions. Auto focus lenses use the infra red mechanism to detect the subject and focus on it. All manual, as well as digital cameras, support auto focus operations. In fact, most mobile phone cameras, such as the one found in the Sony Ericsson K810I, also include auto focus. The lens sensors sense the objects in the frame and use a few parts of the image to focus. However this mechanism will not always fetch good results for you. There are primarily three conditions in which your cameras auto focus system can be fooled. It is better to know the limitations of this advanced function to get the best results. The three situations are-

1. Low Light Conditions- In case of low light conditions, auto focus is not able to function properly. In low light conditions you mostly need to increase the shutter speed, and at an increased shutter speed the camera becomes very sensitive to any kind of movement. So if you use auto focus at a shutter speed of 2 sec, even a single jerk would lead to a blurry image.

2. Far spaced objects- If your frame has too many subjects that are placed at far away distances then your cameras auto focus tends to get confused. In such case the camera either focuses on the nearest object or the farthest object leaving the other out of focus or blurred. Hence in such cases it is advisable to switch to manual focus.

3. Less details- In case of a frame in which there are very less details and a lot of clutter, the camera gets confused as it uses infrared mechanism to focus on one or more areas of the image, but of everything is too scattered it will have a problem deciding. You can make it work by zooming on a particular object or keeping something prominent in the frame.