How to Manually Focus Your Canon EOS 6D
You can have the greatest Canon in the world, but if your images aren't in focus, nobody will care about your pictures. Manual focus can, at times, be the solutions for this problem.
When you shoot images with the lens set to autofocus (AF on Canon lenses) mode, the camera looks for areas of changing contrast or objects that are under autofocus points, and then uses these areas to focus the scene. However, in low light — or when you’re taking a picture of a scene with lots of detail in the foreground and background — the camera may not be able to achieve focus.
The green focus-indicator light in the viewfinder flashes when the camera cannot achieve focus, and you may also notice the autofocus motor on the lens is quite active as the camera tries to achieve focus. When you can't achieve focus, you have no choice but to manually focus the lens. Canon lenses and most third-party lenses give you the option of switching to manual focus.
To manually focus the lens, follow these steps:
Move the Focus switch to MF.
On most lenses, you’ll find this switch on the left side when the camera is facing your subject.
Press the viewfinder to your eye and twist the lens focus ring until your subject is in clear focus.
Concentrate on areas with contrast or sharp lines. This makes it easier for you to see when your subject is in focus. Remember to focus on the center of interest in your scene. If you’re photographing a person, focus on the eyes. The curve of your subject’s eyelid should be in focus in the resulting image; it’s also an easy area to focus on.
Take the picture.
Switch the lens back to autofocus (AF) when lighting conditions permit the camera to focus automatically. If you switch back to autofocus, and the AF motor still racks the lens back and forth but still can’t achieve focus, follow Steps 1 and 2 and get the subject in focus as best you can, and then take the picture.
If you’re focusing manually in low light, shine a penlight on the focal point of your image, the area that should be in focus. When you’re photographing in low light, you should mount the camera on a tripod, which will make it fairly easy to focus on your subject. After you achieve focus, switch off the penlight.
When you mount your camera on a tripod, disable lens image stabilization if the lens is so equipped.