The other day I said “focus using one focus point”. A reader asked why. So let me explain why I said that.
On a modern SLR camera you have many focus points: 9, 11, 22, or even 40. The camera has various modes, which may include:
- The camera chooses from all available points.
- The camera chooses from a smaller area of available points.
- You choose a point, but the camera will look immediately next to that point if it cannot find focus.
- You choose a focus point, period.
- You choose a very small focus point.
Method 1 is the “snapshot” mode. Methods 2, 3 and 5 may only be available on high end or very modern cameras (2 and 5 are only available on my 7D, for example). I like 3, but it too is for high-end cameras only. So usually the choice is “1 or 4?”
In method 1, the camera chooses one or more focus point; in other words, it decides where to focus.
What does it base its choice on?
A lot of people think “on the subject”. No, it does not have a brain, It does not know what the subject is. The camera basically bases its choice on “I’ll focus on whatever is closest”.
And that, as in the image below, is not always what you want. In this image I wanted the wall to be sharp – so I aimed the single focus spot between my fingers.
Which is why you choose method 4: YOU choose a focus point, and aim that at the subject where it should be sharpest.
There are a few things to remember:
- You need to allow enough distance.
- The subject needs to be well lit.
- The subject needs to be contrasty (focusing on a blank white wall is impossible).
- You can recompose after focusing, as long as you keep your finger half way on the shutter.
- On high end cameras, exposure is also biased to the focus point, making it even more important to focus accurately.
Photographers who let the camera decide where to focus are playing roulette – Russian roulette. after all, in a portrait, do I want the closest object (the nose) to be sharp, or the eyes?
So take charge and usually, use one focus point. Focus, wait, recompose if needed, and shoot. Presto – sharp where you want it to be.