While most photographers rely on autofocus (even the pros), sometimes autofocus isn’t the right tool.
Perhaps your camera keeps latching onto the wrong object. Or perhaps using the autofocus assist lamp is drawing too much attention as you try to shoot that dramatic performance. It’s OK — cameras have manual focus for two real reasons: For control freaks and for when autofocus fails to give you the results you want.
Here are a few tips that will help you nail focus (even when you’re adjusting it manually).
Sometimes there’s too little light
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, and over). This is the right time to switch it to manual.
Don’t ignore the points
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 often 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.
Use the focus distance window
Look at the top of your lens. You may find a window with a scale that moves as you twist the focus ring (cheaper kit lenses may not have this window). These numbers can help you get a lens closer to focus (particularly if you know or can estimate the distance of your subject).
You may also have hash marks on your lens (marked with distances) that serve an identical role.
To infinity (and beyond)
Twist your lens 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 in the focus distance window the lens is focused 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 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. Shooting at night? Don’t forget your flashlight so you can see the window!