Auto and Manual focus in Camera

We can focus on subject using manual or automatic method. AF (Auto) and MF (Manual) buttons are used to indicate focus method on most of the cameras.

• Manual Focus - Manually adjust the focus of camera. It provides full control on focus. Most of the lenses will have a button which can be used to switch between manual and auto focus. Manual focus is suitable for situations where subject is stationary.
• Auto Focus - Camera will automatically focus. User can also choose area where camera needs to focus. Most of the cameras will focus on subject when you half press the shutter button but some cameras also come with back button that can be used for focusing.

Here is the list of AF modes.

• Single - For still subject and camera - One-Shot AF (Canon)/AF-S (Nikon)
• Continous - for moving subjects/camera - AI Servo AF (Canon)/AF-C (Nikon) - Camera tries to adjust the focus continuously. It drains lot of battery power.
• Automatic - switches between above 2 modes - AI Focus AF (Canon)/AF-A (Nikon)

If Camera has more AF points, it will be able to quickly focus on any moving objects. AF area setting will be used to determine what area should be used to focus.

Auto Focus Area/Method

Auto Focus Area/Method is used to determine which points to be used to find the focus

• Face tracking
• single point spot
• single point
• Zone AF
• Expanded AF Area

Tips for focusing moving subject

Please refer to this video - https://www.youtube.com/watch?v=NqOKm3Z9zX0 for more details.

• Lock the exposure and focus manually. Or you can take photo (to set the focus) and then switch camera to video mode. If subject is moving, move the camera as well keeping same distance between subject and camera.
• Instead of locking focus, Keep adjusting the focus manually continuously. This is useful when camera man can not move and you want shallow depth of field.
• Use high f-stop value for aperature. This way most of the area will be in focus. But only drawback is that you will lose shallow depth of field. For landscape shots, this approach is better.
• Let camera track the subject using excellent auto focus system. e.g. In canon, we have flexi zone and tracking mode in AF. In felxi zone, you can keep subject inside white rectangle and Camera will focus on that area. In tracking mode, Camera will track faces. This is best if only one face is in frame.