Sharpness of a picture is influenced by shutter speed and by the focal point. A quick shutter speed will freeze your subject and therefore will be sharp. The focal point, is where you want the photo to be sharp. There are two ways to focus: manually and automatic. when focusing manually, you look through the viewfinder (or at your display) and move the focus ring on your lens until your subject is clear. While if you choose to do so automatically, your camera decides what is best.
Using automatic focus (or short: AF) there are two terms to know: focus points and focus mode.
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Focus points are the dots or squares you see when you look through your cameras viewfinder. These points are sensitive spots on the sensor your camera uses to target on. Read your cameras manual to learn how to change these settings. There are roughly four modes:
1. Single Point AF
At Single Point AF you only use one point to set your lens to get a sharp image. This is the usual setting for static subjects like portraits or landscapes.
2. Dynamic Area or Zone AF
Using a dynamic area or zone (depending if you own Nikon or Canon) one focal point is used, but it changes to another point if your subject moves. As you may guess, this setting will be ideal for quickly moving subjects like sports or wildlife.
3. Auto Area AF
Using this setting, your camera will decide whether your subject is moving or static. This setting is the most easy one to use, however, it is not always right!
4. 3D Tracking AF
Optional on some cameras is 3D tracking. Where in Dynamic Area or Zone AF mode your subject may move left to right. The 3D tracking mode will also detect movements towards the camera or away from the camera. This setting is not available on all cameras! Read your user manual to see if your camera supports this feature.
Focus modes are used to control the way your focus points react. On most DSLR’s you can choose between Automatic, Single focus or Continuous focus. If you own a Nikon camera these settings are called AF-S, AF-C, and AF-A. Canon calls it One-Shot AF, AI Servo AF, and AI Focus AF. Just like focus points, these modes are used in different scenarios.
1. AF-S / One Shot AF
AF-S or One Shot AF will tell your focal point to adjust only once when you press the shutter button. This is useful in situations where your subject is static and therefore mostly used in combination with either Single Point AF or Auto Area AF.
2. AF-C / AI Servo AF
In contrast to AF-S, AF-C will continuously refocus as you press the shutter release. So if your subject starts to move, your camera will adjust according the movement of your subject. This is great for wildlife or sports or any type of photography that includes quickly moving subjects.
3. AF-A / AI Focus AF
AF-A or AI Focus AF combines the above two settings. This is ideal for example when you take pictures of children. At one point they sit still, but when they all of a sudden start running, the camera switches to the continuous / servo focus mode. Although this might seem the best setting at all time, it is not. For example, when you are about to make a portrait of somebody and behind the person something starts to move, your camera may pick this up and changes the focus to this area and miss focuses the person. A combination of AF-S and Single Point AF would have been better in this situation.
So for both selecting your focus points and mode, be aware whether your subject is static or moving and select the right setting for it.
Where to focus?
Now you know there are different settings on your camera to get a sharp picture and how to use these settings (basically choose between a static or a moving subject), it also is important to know where your photo should be sharp (focal point). Because the focal point gives the impression of sharpness.
Your subject should always be sharp (there are exceptions for artistic purposes). If you take a picture of a rock, the rock should be sharp, and if you take a picture of somebody, make sure this person is clear. But where do you focus to get your subject sharp? A good question to help you out here is: “What draws the attention to the subject?”.
Portrait (people and animals)
When for example photographing people, pets or wildlife, you should always get the eyes sharp (this is a basic “rule”). Because what draws the attention to a persons face? Right, the eyes! But what if you see a face with bright red lipstick and you want to take a picture of it? Like I said, you are allowed to break the rules. But if the lips draw attention you might want to cover the eyes (exclude them or put sunglasses on), because even when the lips draw the eye, if your subjects eyes are not sharp, the picture will be considered soft in most cases.
Landscape and nature
One of the big differences between portrait and landscape photography is the size of your subject. In a portrait, you want the subject to be sharp and the background soft to keep the viewers eyes on your model. But in landscape, you want to show a larger view. This requires a smaller aperture for a larger depth of field (read my page on that here) and therefore a different focal point. A simple rule in landscape photography is to focus on 1/3th of the picture (if you are deeper into photography read something about the hyper-focal distance here).
And what about infinity?
Sometimes you may choose to focus on infinity (click here to read how and why?). This only can be done if you set your camera and/or lens to manual focus and turn your focus ring on your lens to the infinity symbol (∞). A few situations to aim on infinity is when it is to dark to concentrate on a real point and your subject is far away (like the stars or fireworks).