What is a focus lock?

The autofocus system of a camera works by autofocusing an object in the center of the viewfinder. If the subject is not in the middle of the photo when the shutter button is pressed, the subject will be out of focus because the camera will automatically set the focus and exposure for the subject in the middle of the photo.

In order to focus and expose objects that are not in the middle of the photo correctly, you need to use the focus lock system, which is a system that tells the camera to focus.

First put the subject in the middle of the viewfinder. Then press half of the shutter to lock the focus on the subject. When you press this button, you will hear a click or see the focus indicator (usually a green dot) on the LCD screen light up.

Extended data:

Press and hold the shutter halfway to reposition the subject so that it is not in the middle of the LCD screen. Be careful when reorganizing; Neither you nor your subjects can leave their original positions. Finally, press the shutter completely and take a photo. By locking the focus first, you can focus the object correctly, even if it is not in the middle. Because you don't just take pictures with a subject in the middle, practice this technique so that you can compose freely and keep the focus on the object afterwards.

After the focus is locked, the camera will also set the exposure of the object. In other words, if the focus is locked on a very bright object, the camera will underexpose the whole picture to get the correct exposed object. The effect of this is to make the picture look darker. On the contrary, if the focus is locked on a very dark object, the camera will overexpose the whole photo, which will make the photo look brighter.