Your camera’s autofocus system is a well-designed, intelligent piece of technology, but like those computers that play chess, sometimes they get confused and need some human intervention! But the key to getting good images in these situations is knowing when your AF system is likely to struggle. Below we round up the most common instances when you need to take control of your focusing.
01 Low contrast subjects
AF systems can have difficulty locking on to subjects with overall low contrast or low-contrast subjects framed against a low-contrast background.
Likewise, your autofocus will also struggle to find your focal point if your subject is the same colour as your background.
How to fix it
Switching to manual focus is the best way to ensure precise focus. If your camera has Focus Peaking, this will help you fine tune those fine details.
02 Low light
It makes sense: when there is less light, your camera’s AF system has trouble ‘seeing’ its target. This is especially true if you’re using a telephoto or macro lens where depth of field is limited and light levels a bit lower.
How to fix it
Again, manual focus gives you the control to make precise adjustments. But your AF Assist feature or a flashgun can also help here.
03 Reflective subjects
Subjects with highly reflective surfaces can cause your AF system to panic. Glass-fronted buildings, mirrors, cars or anything shiny and metal will pose a challenge.
How to fix it
Your camera’s AF Lock feature is a quick and easy solution to locking in your focus. And, again, taking control with manual focus. Are you sensing a theme?
04 Strong contrast / different levels of brightness
A really striking portrait that we often see is a model’s face half-shrouded by shadow. When you have areas of greatly differing brightness within a scene, your AF system can get confused.
How to fix it
Use your AF Lock or manual focus
05 Repeating patterns
Subjects such as office buildings and tower blocks can flummox even the best autofocus system. When geometric patterns like this repeat throughout a scene, your camera can’t ascertain what it is you want to be your focal point.
How to fix it
Switch to manual focus and choose the area of the scene you want to be in focus. If your camera offers Focus Peaking, this can help you ensure the image is crisp where it needs to be.
06 Overlapping elements
Much like a repeating pattern, an AF system will struggle to lock onto a subject if it’s being overlapped by another element within the frame. This is particularly true if that overlapping element is closer to your camera. Think of an animal at the zoo, for instance. When you try to focus your AF system will likely lock onto the bars of the cage.
How to fix it
Can you guess… focus manually! Again, Focus Peaking – a brilliant feature in modern cameras – will help you not only get that animal’s face sharp rather than the bars, but you can magnify the scene and make sure those eyes are pin-sharp.
07 Small subjects
If your focus area contains, for instance, part of your foreground and a building in the distance, your camera’s AF system won’t understand where you want it to focus. When your subject is smaller than your focus area, you’re going to have problems.
How to fix it
Zoom in if you can, and use your AF Lock feature.
08 Off-centre subjects
This is probably the one on this list that nags everyone the most. We’ve all wanted to get creative with our framing only to be let down by our AF. When your subject doesn’t sit in the central focus area, sometimes your AF system can hunt trying to find it. Modern AF systems have got better at this, but for many of us the struggle is still real!
How to fix it
Use your AF Lock tool and lock focus on your daughter’s eye, or whatever it is you’re framing off-centre. Then re-compose the shot and take the picture.
09 Too many fine details
This is another real bugbear. If you’re shooting an outdoor portrait in the city, for instance, if your family is set against an architectural background with lots of patterns and details, your AF system isn’t going to perform so well. The same occurs indoors, in a field of flowers or even when subjects are small and of a similar level of brightness as other objects in the scene.
How to fix it
Focus manually! It’s the only way.