You have to know when to use manual focus to get the perfect results.
This article will help you understand why and when manual focusing is the best thing to do. You will learn tips on how to make the most of it – and how to have more confidence to use it in certain situations instead of auto-focus.
As DSLR owners, we have the best of both worlds between manual and automatic focusing; we have a choice as to how we decide the subject of our photo, and other points that aren’t as important. This is an advantage for you, and having a better understanding of the “other” focusing method will allow you more flexibility and leave you better prepared for a wider array of situations while in the field. But keep in mind, you’re not learning manual focus as a replacement for automatic focus, you’re learning it as a compliment.
So what shooting situations might benefit from the wonders of focusing like our forefathers?
When you’re shooting macro or close-up photography, you’re usually dealing with an extremely thin depth of field. At larger apertures, focusing is extremely important. Manual focus allows you to ensure that the most important part of your subject is crisp.
As wonderful as autofocus is, it tends to falter a bit in low-light situations, the amount of which usually depends on the lens being used. You’ve undoubtably experienced times where the autofocus struggles to find a focal point, and leaves you with nothing more than a blurry preview through the viewfinder.
When shooting with a wide-angle lens, particularly in landscape photography, your subjects can tend to be a larger objects shown on a smaller scale, such as trees, buildings, and other inanimate objects. In this situation, since they occupy a smaller area of the frame, controlling the focus of the shot on your own will usually yield better results.
There are also times where you may prefer to control your focus for creative reasons. Shooting a model through a frame of trees, for example, or requiring the background of the photo to be in focus while the foreground is not.
While modern autofocus system can usually get this right, manual focus allows you a level of control that’s hard to automate.
Low contrast situations
Autofocus on modern cameras work best when there is a higher level of contrast between the dark and light tones within an image. These systems tend to struggle when contrast in the frame is reduced, such as shooting a light-colored subject against a bright background.
Source: Digital Photography School