Auto focus is of unquestionable benefit in a large variety of shooting scenarios, but there are often times when it could actually be wiser to plump for manual focus. In these scenarios, which are outlined below, it is fair to say that autofocus doesn’t perform as well on some cameras, so simply rotate the focus mode selector to M and use the focus ring to sharpen the subject in view. It is also worth remembering that it can be easier in some situations to use the focus lock, in this instance simply focus on another subject at the same distance and then recompose the frame accordingly.
1. Fine details in close proximity
When shooting a scene that compromises hundreds of elements – each presenting a multitude of details – manual focus may be necessary for complete control. This is especially necessary when the subject(s) exhibits small or no variation in size, shape, colour or brightness. For example a field of flowers, a nature abstract close up, a busy high street packed with pedestrians etc.
2. Obstacles are in the way
If your subject is partially blocked behind an obstacle that you are unable to move out of the way or intend to keep (adding context), manual focus can help you to pinpoint the main subject. Furthermore if you team this approach with a wide aperture, you can creatively blur the obstruction from view. For example a caged or penned animal, a person looking from a window or stood behind a gate etc.
3. Geometric confusion
Many architectural photographers, especially those favouring contemporary design will often favour manual focus over auto. This is because modern architecture often exhibits geometric patterns that can confuse the camera’s auto focus. For example those shown on skyscrapers.
4. High contrast
When presented with a scene that contains large areas of sharply contrasting brightness it is likely your autofocus will struggle. For example if you are shooting an outdoor portrait with the subject stood in the shade, but have decided to incorporate a large area of adjoining light.
5. No contrast
As with areas of high contrast, photographers may find that scenes with no contrast present the same focusing issues, i.e. the main subject of your image exhibits the same tones and colours as its background. A common example of this is a freshly built snowman in a field of crisp white snow.
6. Dominating features
Compositions that contain objects that are bigger or bolder than the intended subject may also throw off your autofocus. For instance a person dwarfed in front of an intimidating cityscape may be lost using autofocus, switch to manual for a quick and effective solution.
In situations where you want to shoot in complete darkness you may find manual focus is your only option. Examples of when this may be true include: shooting star trials, the northern lights or creating light graffiti. Often focusing at night is a case of trial and error, so scrutinize results by zooming in to the images presented on your LCD and adjust accordingly.