Precise Focussing with Your Digital Camera
Inaccurate Focussing
Leaving your cameras focussing system to multi-point auto focus is a poor way of focussing. It’s like playing Russian roulette. Getting a precise focus point is a game of chance and the most important parts of your scene or subject might not be sharply focussed.
Why does this happen?
Because the multiple focus points lock onto the nearest, high contrast thing that they ‘see’, and this high contrast area might not be where you want to place your focus.
Typical examples are photos of people, where the nose is in sharp focus but the eyes, the most important feature in any portrait, aren’t as sharp as they should be; or landscape photos where the one part of the scene is sharp but other important parts of the scene are out of focus.
In the above examples: the nose is closer to the camera than the person’s eyes, so the focus locks onto the nose. In the landscape photo, the auto-focus might have locked onto a nearby tree branch or fence instead of further into the scene.
This often occurs when you leave your camera’s multi-point auto focus to ‘do its own thing’. Naughty camera.
So how do you avoid inaccurate auto-focussing?
For most modern digital cameras, there are three options:
Option 1) Set your focussing mode to manual and focus by hand, whilst looking through the viewfinder. (OK if you have good eyesight but this method can be slow).
Option 2) Disable the multiple auto-focus points and set a single (moveable) focus point. (Quick and accurate).
Option 3) Use Live View mode and focus manually whilst viewing the LCD.
This can be a very precise but takes time and is not practical when hand holding your camera. Using Live View mode also drains your battery quickly, so carry a spare if you intend to use this method.
Setting Single Point Focus?
Changing to a single focus point is available for most cameras and it’s easy to do. Check your camera manual for how to set it on your particular camera.
Using Single Point Focus
a) You’ll see the single, fixed focus point illuminated in your view finder when you half press your shutter button.
b) Make sure that this single point is directly over the most important part of your image (e.g. a person’s eyes or other important part of the scene or subject).
c) Half press your shutter button to lock focus on the targeted spot.
d) Then, press the shutter fully to take the shot.
Many cameras also allow you to move this focus point to different parts of your view-finder (not just the centre position), to allow you to lock onto different parts of the scene or subject. This very useful if you are using a tripod and want to keep your camera in a fixed position.
I prefer Option 2 and use it when I am hand-holding my camera for portraits etc. You can also use this method when you are using a tripod.
Using Live View Mode
a) Switch from auto focus to manual focus.
b) Turn on Live View.
c) Zoom into the important parts of the scene/subject using the magnification x5 or x10 button.
d) Check your LCD panel and manually focus to bring the important areas into sharp focus.
e) Zoom out and fully press your shutter button to take the shot.
Dealing With Other Auto Focussing Problems
1) Low Contrast, Featureless Subjects
I mentioned at the start of this article that auto focus locks onto areas of high contrast. When your subject is mostly featureless, with large areas of low contrast, auto focus struggles to find anything to lock on to. You might hear your auto focus ‘hunting’, whizzing in and out trying to lock. Failure to lock focus can prevent you from fully pressing your camera’s shutter. No auto focus, no picture.
So what do you do in these circumstances?
Point your focus point over a high contrast edge. In the case of skies, the edge of clouds. For water, look for convenient boulders or edges of shadows. if you can’t find anything suitable, revert to manual or Live View focus.
2) Focussing in Low Light Conditions
Similar problems occur when you are taking pictures in the dark, where your subject not well illuminated. Your auto focus can’t lock due to the low contrast. In these circumstances, your camera may emit a focus assisting beam of light, which enables the auto focus to lock onto anything illuminated by it. (Some cameras need to be in fixed auto focus mode for this to work). If you are using hot-shoe mounted speedlites/speelights, these emit an infra red focus assisting beam that helps to lock focus. No focus assisting beam of light from camera or flash unit? Instead, use a small torch to illuminate your subject.
Summary
Don’t play Russian roulette with your focus point; choose a focussing method that enables you to focus precisely.
Author: Mark Elliott www.better-photos.co.uk












