Focusing right may seem easy, but there are a number of factors to consider to succeed in taking a good picture. When photographing, you can either use autofocus, which means that the camera sets the focus in the image or focus manually, that is, you set the focus in the image yourself on what you want to focus on. Autofocus is usually preferred as it is both fast and helps you take pictures with good sharpness. Nevertheless, there may be times when you would rather use manual focus. An example of this is if the camera has difficulty understanding what in the image is your subject and instead focuses on something else and if it is difficult for the camera to interpret the contour in the image. Ie if it is very bright or if it is very dark, the camera has difficulty finding the focus itself and then needs you to help it.