The way I see it, your camera does three things to make a picture: focuses, adjusts brightness, and adjusts color. I know that’s a simplified description, but to me as a creative, that’s all that matters. And the one that matters most is focus.
Nothing directs your viewer’s eye as quickly and as powerfully as focus. Making one thing in an image crystal clear communicates that that thing is important. It’s also the privilege of photography to be the only medium capable of displaying clarity and sharpness with more-than-real definition, so it’s imperative that we get this right.
Unfortunately, your camera has all the automatic options enabled, and it doesn’t know what’s important in your picture. There’s nothing worse than recording a beautiful moment with only the background in crystal clear focus. Focus is also the one thing that absolutely can’t be ‘fixed’ in photoshop. (Although, CC’s new blur sharpening is pretty incredible.)
As we talk about autofocus I have a few prerequisite notes. First, autofocus means letting the camera move the lens to focus. I use autofocus all the time–it is so good and so fast I couldn’t keep up otherwise. Within the autofocus options on your camera, there are a few automatic settings, and those I don’t use. Second, focus is all about distance. When you focus on a face, you aren’t only focussed on the face, you are focussed on everything that is the same distance away as the face. Your camera doesn’t focus on faces or rocks or trees or soccer balls; it focusses 10 feet away (3 meters), or 100 feet away. Knowing that, let’s set your camera up to focus at the distances you choose. Lastly, this is a beginner/intermediate article. If you’re a master of 3D dynamic tracking, you’re beyond this article, so cut me some slack (but maybe I can give you some language that will help you explain things to the newbie next door).
Focus in your camera has two parts. First is the part that let’s you choose where to focus–focus area mode. On automatic, when you press the focus button you see several squares in the viewfinder light up, and if you press it again they may light up somewhere else in the frame leading you to believe that all those things will be in focus. That’s far too random and inconsistent, though. You need to switch it to a single focus point that you can place in the frame where you want it. (usually by moving the arrow keys on the back of the camera). The options in most cameras are auto and single/manual. I can safely say that I never use automatic selection. When you’ve got one focus point, you can choose where to place it in the frame, and that’s a powerful picture making tool.
Now that you’ve got a single focus point, we need to control the part about what that point does. Your camera is capable of focussing and holding focus at that distance (like on a person’s face in a portrait) or it can also continuously change focus as your subject moves closer or farther from you (like a soccer player or a bird). Naturally, the automatic option (AF-A on Nikon or AI Focus on Canon) is supposed to know when your subject is holding still and know when it’s moving and refocus. Unfortunately, it’s just not that smart. The other options are AF-S/One Shot, or AF-C/AI Servo (by the way, in AI Servo that’s a capital ‘I’, not a lower case ‘L’).
AF-S or One Shot–Use This!
Frequently, I don’t have a focus point in the part of the frame that I want to focus on, like in this portrait of T. I needed to focus on her face, but it was just outside the focus point, which means the camera may have focussed on her shoulder or her ear instead of her eyes. Using AF-S/One Shot I placed the focus point on her face, focussed, held the shutter button half way down, and moved the camera to reframe her in the right spot. If I tried that in AF-A/AI Focus the camera would refocus after I recomposed because it will think that the subject moved, giving a wonderfully sharp, crisp background and a fuzzy subject. Using AF-S/One Shot I can shoot portraits, flowers, landscapes–anything that doesn’t move while I’m shooting–and I keep the subject sharp by focussing and recomposing. That’s what most of us shoot most of the time, and that’s the mode you should use most of the time, too.
Another reason to use AF-S/One Shot is that not all focus points are created equal. The focus point requires contrast and light to do its job. Contrast usually means strong texture or a line differentiating two different colors or tones. That means it’s easier to focus on the edge of a chair than it is to focus on a blank wall because the wall has nothing to indicate how far away it is. Your focus points can see either vertical or horizontal lines to focus on, but the centermost focus point can see both (it’s a cross-type and many cameras have more than one). That makes the center point more powerful in tricky situations, which is the only time it matters. And the most common tricky situation is when you are shooting in low light (meaning anything other than bright daylight). Your lens is markedly brighter in the center, letting more light in, which also makes it easier for the focus points nearer the center of the picture to work. So, because the center point is better and because it’s brighter, it will focus more accurately in the dark. Put the focus point in the center, focus on your subject and hold the shutter button halfway down then recompose so the subject isn’t dead center, and finish by pressing the shutter all the way down.
AF-C and AI Servo
If you’re like me, you’ve got pictures of your nephew playing soccer where he is running down the field and is out of focus and the guy right behind him is nice and crisp. That’s because the camera focussed at the distance where he was, but by the time I finished making the picture he had already moved closer (and now the other guy has entered the focal plane). That can be so frustrating, and in cases like the eagle above, if it’s not perfectly focussed it’s not worth viewing.
AF-C or AI Servo can solve this problem for you. Choose this mode and, looking through the viewfinder, place the focus point on your subject. As long as you keep the button pressed halfway down, the camera will continuously adjust the focus to keep the subject sharp. Hopefully.
There are a couple of things that will help you maximize this mode. As with AF-S/One Shot, the center focus point is the most accurate. The camera still requires contrast to focus, so good luck tracking a white volleyball on a white sandy beach (white soccer balls on green fields are much easier). Next, keeping focus is easier than acquiring it again. Practice tracking with your subjects and keeping the focus point in the same place on the subject (practice by tracking with cars as they drive by). Lastly, focus tracks better if there is a great distance between the backdrop and your subject. Bald eagles with mountains a few miles away are ideal subjects: white head on dark body makes good contrast, it’s easy to track, and the background is far away making the distinction simple for the camera.
Don’t get frustrated if you don’t nail every action shot you make. With practice you’ll get better, and know that your camera has huge limitations in this area. Pros who shoot sports for a living pay more than $5000 for the camera body alone, and the one feature that is hugely better than lesser cameras is the continuous autofocus.
Sometimes autofocus isn’t the right tool, but here are a couple of things that will help you nail focus even when you’re adjusting it manually. Sometimes it’s just too dark for your autofocus to make the right adjustment–you’ll know it because the lens will just keep turning in and out over and over. This is the right time to switch it to manual. Fortunately, even though the camera can’t focus itself, you can still use the focus points to know when you’re in focus. Position the focus point on your subject and as you twist the focus ring on the lens pay attention to the focus indicator in the viewfinder; it’s usually a little green circle in the bottom corner of the viewfinder, and it may blink or switch to an arrow when the subject is out of focus. Just turn the ring until that light is solid green and you’re all set.
Finally, look at the top of your lens and you may find a window with a scale that moves as you twist the focus ring (the cheapest kit lenses may not have this window). Twist all the way to one end and you’ll note an infinity symbol (looks like a figure eight on its side). When you set that infinity mark at the hash mark on the window the lens is focussed as far away as it can be. When would you use this? When shooting at night you’ll find that it’s very hard to focus on the stars, or even a mountain’s silhouette. Setting the lens to this mark will put the stars or that mountain in focus. Note that that mark is not necessarily at the end of the focus ring’s movement. Many lenses will twist past infinity and then they are actually out of focus, so it’s important that you set the lens to this mark. Just don’t forget your flashlight so you can see the window!
Autofocus is such a powerful tool, and it’s what really sets today’s cameras apart and allows average people like you and me to pick up a camera and make a decent picture right out of the box. Can you imagine how it was for all those before us who had to focus manually for every shot, and still had to capture life’s moments in a split second? My first camera was manual focus only, and I can tell you that autofocus has launched my learning light years ahead.
There are many more things those little autofocus elves in your camera can do, and these tips only scratch the surface. But these have really helped me get control of this wonderful picture making tool, and I know they’ll help you step up to the next level, too.
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