Getting consistently sharp photos can sometimes be a challenge, and it might be the most important challenge that beginning photographers have to overcome. Although things like contrast, color saturation and white balance can be tweaked in post-processing with a little know how, a blurry photo is a blurry photo. You can make it look a little better, but you can never really make it sharp.
The key to fixing a blurry image, then, is to avoid taking blurry images. Fortunately your DSLR is a very sophisticated machine, and it gives you a lot of tools to help you take sharp photographs. Let's look at a few methods for choosing your focus point.
What are focus points?
All modern cameras have focus points - some have as few as three, some have many more than that (the latest Nikon cameras have 51). A focus point is simply a point at which the camera can lock focus. Obviously, the more focus points a camera has, the more likely it is that you are going to be able to get a tack sharp image. But it's not always as simple as that. To know where to lock focus, a camera has to know what your subject is. It also has to know what point on the subject is the most important and the one that should be the sharpest. To make this decision, it can either guess, or you can tell it.
Focal Points for Point and Shoot cameras
Point and shoot cameras don't have the focal point settings that I discuss in the rest of the article. To set the focal point on your point and shoot camera, touch the screen at the back of the camera at the point where you want it to focus. It will focus the image at that point, and usually show you a square when it has locked focus.
Those Auto Settings
By default, your camera likely has all the focus points turned on. That means it's using those points to choose where to focus. Most photographers never take their cameras out of this mode - they just press the shutter down halfway and then let the camera decide what to focus on. A very sophisticated camera can actually evaluate a scene and make a judgment call about what the subject might be, and then select a focal point based on where that subject is in the frame. This typically works well when you are shooting at a small aperture (high f-stop) or have a simple composition. On the other hand if you are opening up that aperture or have multiple things in frame that your camera could focus on, you may end up with a blurry subject.
This photo was shot using the focus/recompose method.Grabbing Hand by Flickr user brtsergio
Focus and Recompose
The simplest, most non having-to-mess-with-camera-settings way to tell your camera exactly where you want it to focus is to use the focus and recompose method. This is accomplished using focus-lock, which on most cameras is a quite low-tech function. To use focus-lock, center your subject in your viewfinder and press your shutter button down halfway to focus. Then recompose - move your camera so that your subject is on that rule of thirds intersection, for example - and shoot.
Sony RX1, A User Report by Flickr user kern.justin
Single Point AF
Modern DSLRs give you a few different alternate ways to focus your camera. One of the least complicated but most useful is single point mode. In single point mode, you manually choose where you want the camera to focus. Once you've put the camera into this mode, you'll see set of focus point brackets through your viewfinder, and you can use the joystick on the back of your camera to move the focal point until it lands on the precise point where you want your image to be sharpest - your subject's eye, for example, or the stamen of a flower.
Using single point AF is one way to nail your focus every time, because you have complete control over what part of the image your camera is going to lock on to when you take the picture. Using the automatic grid system is a bit of a gamble - it's like trying to get a ping pong ball into one of those carnival goldfish bowls. OK maybe not that challenging, but you get the idea. Your camera will try to get the focus right, but it won't always succeed. The only way it's going to get the focus right every single time is if you tell it where the focus should be, every single time.
I'm the first to admit that using single point AF can be a little clunky at first. If you're taking a series of photographs and your subject isn't staying in exactly the same place, you're going to spend a lot of time moving around that joystick and less time taking pictures. Use single point AF enough, though, and eventually it's going to become second nature - just like it that halfway-down-to-focus shutter button became second nature after you'd been using your DSLR for a while.
Greater Shearwater by Flickr user cotinis
Drawbacks of single point AF
Birds in flight are notoriously difficult to photograph with single-point AF, because they move fast and don't always go in a predictable direction.
There's always some drawbacks, aren't there? Single Point AF works best when you're shooting subjects that don't move fast or erratically, for obvious reasons. If you try to toggle that focus point around while a hawk is diving in after a field mouse, you're going to miss the shot. If you're trying to follow a dancer on stage with your joystick, you're going to miss the shot and also irritate everyone around you when you start moaning about how you just missed the shot. Quickly moving subjects and subjects that are moving in an unpredictable pattern need different focusing techniques/settings. Sporting events are a good example of scenes that won't benefit from single point AF. Wildlife is also difficult to photograph with single point AF.
I'll bet your starting to see a common theme in these lessons - auto is OK, but it's no match for the human eye. Like anything in photography, you need to make a choice about what is most important. If you have to shoot fast and if your subject is unpredictable, sticking with that auto setting might be a good idea. For all other situations, take control of your camera's focus. Choose single point AF and you'll see a big decrease in those unusable, unfixable, blurry photos.
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