Introduction of common focusing modes

Introduction of Focus Mode 1: Manual Focus (MF)

In some cases, autofocus is not very good, such as the scene is too dark, the subject lacks a clear contrast area, shooting through a cage, or the subject moves too fast or irregularly. In these cases, manual focusing may be more effective.

Switch to manual focusing (through the camera body or lens) before manually adjusting the focus ring. The lens using ultrasonic motor may be able to focus manually in AF mode, but the standard autofocus lens should only focus manually in MF mode, otherwise the AF motor will be damaged.

The subject is focused until it clearly appears in the viewfinder. The object may be anywhere in the picture, so it can be composed before focusing. However, if the AF sensor is focused manually when it is on an object, the camera usually displays a confirmation signal when it reaches the clearest focus. This feedback is useful when it is difficult to visually determine whether the focus is accurate.

Manual focusing is also useful when you want to get the maximum depth of field with a small aperture. When using a wide-angle lens, set the focal length between the camera and the DOF area to be covered to 1/3. For example, you want to make the scene from 5 to 5 to 5~50m meters clear. The total depth of field is 45m. Therefore, we should focus at about 15m in the scene or 20m away from the camera. When using a telephoto lens, you should focus on half the DOF area. These ratios are only approximate; You should use the DOF preview button on the camera (if any) to check whether the DOF really covers the required scope. You can also view the image on the LCD instead of the d of preview.

Introduction of Focus Mode II: Multiple autofocus sensors

Most DSLR have multiple autofocus sensors, so you can choose to use one or more sensors at the same time. If the subject is obvious and the closest subject in the picture, especially when the subject is walking around, all autofocus sensors can be activated. Combining multiple sensors can cover a wider range and focus faster.

If the subject is not obvious, or other objects in the viewfinder are closer, only the central sensor should be used. Using the autofocus point can be free from interference from other autofocus sensors, because other sensors may focus on other objects. In addition, the central autofocus point is usually more sensitive, while the others are less sensitive. This method should be chosen in a more demanding situation, such as when moving quickly.

Introduce three focusing modes: A-DEP mode.

This mode is available on some Canon DSLR. It actually combines exposure and focus modes. A-DEP means automatic depth of field, which uses all the AF sensors of the camera to detect the nearest and farthest points covered by these sensors. Then, it chooses an aperture to provide enough depth of field to cover the range. Finally, the camera sets the focal length so that the obtained DOF can cover the selected scene.

This paper introduces the fourth focusing mode: single-shot AF.

This is a common setting when the distance between you and the subject is fixed. Aim at the camera, and then its autofocus sensor illuminates the subject. Click the shutter button to activate autofocus. After determining the focal length, the camera sends a signal in the viewfinder to stop focusing. As long as the button is half pressed, the focal length will be locked at the current position. Now you can take a picture (even if the AF sensor is no longer facing the subject), and then press the shutter button completely to take a picture. Usually, if the camera doesn't get the right focus, it can't shoot. This is called focal length priority.

Introduce 5-band focusing mode: continuous autofocus.

This is usually used in sports or action photography, when the subject is constantly moving (for photographers). Place the autofocus sensor on the subject and press the shutter button halfway. As long as the shutter button remains half pressed, the camera will continue to focus. When the button is fully pressed, the camera will take a picture, whether the image is in perfect focus or not. This is called release priority.