how to focus in photography

control your camera focus – manual focus vs autofocus

Today we are going to talk about how to camera is focusing the image, manual focus versus automatic focus. This topic should be an easy one as probably it takes just few seconds for anyone to understand what focus is and how it works

What is focus and why are we attracted by camera manufacturers by many focus points?

Focus is basically the point or the average distance where the image is sharp. It is not a single point but a distance measured in depth from the camera. The focus can be very deep, starting with full image in focus and nothing blurry, or very narrow where you can see a sharpness for only few millimetres depth – as example the macro photography where you can see an ring for example – the front part is blurry, sharpness at the back of the ring, and in 2 or 3 mm further the image becomes blurry again. The focus is controlled by the lens. What happens is that the camera will preview an image, and measure the distance to the subject and tells the lens how to arrange the internal components to focus on the desired point. How it measures the distance is not important. What we need to know is that there is a limited depth where the focus works, and that is given by the lens on the first hand, and the aperture at the second. It is useless to attempt to get a narrow focus without the proper lens, regardless of the aperture.

Automatic focus

The easiest task in photography is to focus automatically. The only thing you need to do is point the camera towards the subject, half press the shutter button and the camera will focus for you. Press to the end and you took the picture. In many cases this is enough if the subject is clear in your picture, and there are no intention to blur parts of the image in particular. All cameras have automatic focus, and we need to understand that in reality this is the task of the lens, but the camera will tell the lens what to do

Before going any further I would like to destroy to myth of the camera manufacturers attracting people with more and more focus points as being a better camera. If the image wil have many elements situated on various distances from you, the camera will estimate few important points in the , usually measured on colour contrast, and will estimate a point in the average centre of gravity, and focus in between. That will give you an image where there is no control on the depth, and you might have elements out of focus that you want them sharp. AS a professional photographer I have never used more than one point of focus, and everything else is just marketing for people who do not know photography.

Me technique is very simple. I visually select the point I want to focus on, like the eyes of the person in front of me, half press the button until the focus is locked, re arrange the camera to suit my intended frame and press the shutter button to the end. This way I am sure my focus is where I want it and the camera does not do any estimation or approximation for me.

Manual Focus

If you want to be able to control which part of the image should be in focus and others should be blurry, than you need to switch on manual mode and rotate the focus ring of the lens until you get the desired effect. Manual focus will stay as you leave it and will not modify until you want to. Manual focus is useful when the camera does not have enough light to pick a point in the scene, due to maybe low light conditions, or lack of contrast. The problem with the manual focus is that if your eyesight is not perfect, you might see the scene differently than the camera and you might end up with the wrong focus

I usually use automatic focus most of the time. Manual focus comes very handy with macro photography, where it is a challenge to focus on a half a millimetre deep inscription on the back of the ring, or see a small insect eyes.

Challenges in focus

I would say there are few challenges to focus

1- focus in low light. When there is dark outside, you will notice that camera cannot find a focus point. To overcome this issue, switch to manual, or maybe light the subject with a light torch and focus.

2-focus on moving subjects:

There are instances when the subject moves and you loose focus within a fraction of a second. To overcome this issue is to switch your focus on Servo Focus, which will follow the moving subject and will keep focusing until the shutter triggers. This a simple technique to take sport photos in movement. Also focusing on moving subjects, one can follow with the camera, and use a lens with an Image stabilizer. We are going to talk about this in a separate tutorial.

3-extreme backlight or highly reflective objects

4-repetitive patterns or lack of detail

Focus Modes

One Shot focus

– when your camera will lock in the focus on the subject after half pressing the shutter button. I use that 90% of the time and that is the most used focusing mode

Servo Focus:

– when the subject is moving, or starts to move. You lock in the focus on the subject and the camera will follow with a variable focus on the moving subject. good for sports and action and whenever it is movement obviously. Is useful when shooting high number of shots to capture the action.

I use this mode when I am asking people to run, shoot repetitively 20-30 images to get running effects and dynamic images

Other than that focusing should no be a big issue and you will get used to it by practicing, and also depending on your camera. Various brands focus with different speeds and accuracy levels.

link to the youtube video

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