Note: This excerpt from our new book titled The Nikon Autofocus System, Mastering Focus for Sharp Images Every Time has been edited to include information on both Canon and Nikon DSLRs.
Most newer Nikon and Canon DSLR cameras have a Live View mode that you use for capturing video and still photography. Live View in early Nikon & Canon cameras was a bit cumbersome to use. These early bugs have been worked out in newer cameras and now Live View is a breeze to use. Even though focusing in Live View mode is slower, it is definitely the most accurate way to focus for non-moving subjects.
There are many reasons to use Live View:
– Composing product and still images for magazines and advertising
– Obtaining critical focus for macro shots
– Composing images when the camera is low to the ground to avoid lying down to look through the viewfinder
– Composing images when you hold the camera overhead, like when you take a photo over a crowd of people
– Shooting video
Most newer Nikon and Canon DSLRs use either a Live View button or a Live View switch. For models like the Nikon D810 or Canon EOS 5D Mk III that capture both video and still photographs, you’ll need to make sure you select the correct capture mode. Autofocus generally works the same way in photo Live View mode or video Live View mode, but be sure to set the camera for still photos if that’s what you will be shooting.
Live View uses a different AF technology than regular AF on Nikon and Canon cameras. Live View uses contrast detection from the camera’s imaging sensor, as opposed to the phase shift sensors used by the camera’s AF sensor system. Live View AF doesn’t use predefined focus positions so that means the focus point can be located anywhere in the screen, or field of view.
Focusing with Live View is more accurate because you are able to focus the lens with the actual plane of the imaging sensor. If the imaging sensor (CCD or CMOS) looks sharp, the resulting photo will be sharp. In traditional focusing with the camera’s autofocus module, you must trust that the AF sensor is calibrated. When the AF sensor thinks the subject is sharp, that is how the image will be captured on the imaging sensor after the mirror flips up and the shutter curtain moves out of the way. Focusing on the imaging sensor with Live View removes the AF sensors and the mirror from the equation.
The camera’s traditional AF system is very fast and allows you to track moving subjects. Of course, you have to look through the viewfinder to keep the sensors on the subject. Live View focus, on the other hand, is very slow in comparison and doesn’t work well with moving subjects. It works best when you focus on static scenes and the camera is on a tripod or very stable.
Here are some best practices for using Live View photography and video modes:
1. For still photography in Live View mode, I recommend setting the Live View AF system to AF-S (single servo) mode and normal focus area. These two settings result in the most accurate focus and is easiest to use.
2. To initiate focus in Live View, press the shutter-release button halfway or press the AF-ON button (back focus button). Look for the focus box to turn from red to green. When the box is green, the camera has achieved focus for the subject inside the box. When the box is red, the camera thinks the subject is out of focus.
3. To obtain critical focus on the subject, press the zoom button on the back of the camera. It allows you zoom in to the subject on the LCD monitor to really dial in the focus. At this high magnification, you can manually or automatically focus to make sure the shot will be crisp.
4. For shooting videos, I recommend turning off the AF system. The Live View AF modes that allow subject tracking are not reliable and often result in focus hunting, which makes it nearly unbearable to watch the resulting video.
5. Live View automatically actives the VR/IS (vibration reduction/image stabilization) system in your lens. Any time the Live View screen is on, your lens is actively reducing vibration. If you are using a tripod to shoot video, I recommend turning off VR. If you are handholding your camera in Live View mode, keep VR turned on to either the normal or active setting.
Interested in learning more about autofocus on Nikon cameras? Check out our brand new book titled The Nikon Autofocus System, Mastering Focus for Sharp Images Every Time.