Photography Skills-How to Focus

When the camera leaves the factory, it is set to the default configuration, that is, you can keep focus by pressing the shutter. If the camera is set to single autofocus, all you need to do is activate the autofocus sensor and observe the viewfinder (assuming you only have one choice), and the focus of the important part of the scene will be clear. If you focus by half pressing the shutter, the lens will automatically focus on this point. Just press the shutter to take this photo. Although in most cases, you will want to change the composition. Press the shutter for half a time, you can recompose the composition in the way you like, and then press the shutter all the time to finish shooting. This focusing method is especially suitable for hand-held photography.

This method is inconvenient or useless on a tripod, because it is necessary to focus on the composition first, and then lock the tripod head, which slows down the shooting speed. The bigger problem is that you need to keep pressing the shutter button. For most cameras, if you point at the focus that you think is clear, such as deer's eye, and then re-compose it, and then press the cable to release it, the image may not be clear. The reason is that the autofocus sensor may be moved to change the focus from the face to a point in the background when the composition is re-composed. When you start to release the cable, autofocus is activated again, quickly focusing on the background and keeping the deer out of focus.

Continuous autofocus

This mode is very suitable for tracking moving subjects, because it will keep autofocus no matter whether the lens moves closer or farther. Usually continuous autofocus is on the camera body, which may be the choice of a switch or a series of buttons. Continuous autofocus can also be started by the shutter button.

For example, we used a 300 mm telephoto lens to photograph a black-and-white vulture hovering over the body of a Kenyan lion. Using the continuous autofocus function, when the vulture approaches, it is set as the autofocus center, and then it moves along with its flight trajectory to keep the autofocus point on it all the time. When it enters the viewfinder, you can get many pictures by pressing the shutter. Because the camera can automatically adjust the focal length when the distance of the subject changes, the chances of taking clear photos are greatly increased. Just be sure to use the shutter speed of11000 seconds. Following the theme of translation requires constant training to improve.

If the autofocus sensor "sees" the cloud behind the subject, it will re-lock the new target and the vulture will lose focus. Using a large lens with an aperture of f/4 on the tripod, such as 600mm, has a very good follow-up performance. This kind of large and heavy super telephoto lens is impossible for ordinary people to hold effectively and needs to be installed on a tripod. Suppose you photographed a sandhill crane in a wildlife sanctuary. A heavy tripod is used to support the whole weight of the huge lens and the tripod head, so that the camera and lens on the tripod head can be successfully balanced, so if the tripod head is not locked, it can move in any direction. When the sandhill crane approaches, aim at it to start autofocus. As it moves and sees a good composition, you can press the shutter at any time.