Long gone are the times when your only way of making sure your subject is sharp was by the manual focus on your lens barrel. Today, digital camera focus modes are not just plentiful. They offer immense power and capability to handle just about any shooting situation!
But how exactly do the different focus modes on your camera work? What are the strengths and weaknesses of each? And how do you know you’ve selected the right one for the job??
Today, we’ll explore just these questions and more.
What are Camera Focus Modes Used For?
By offering different focus modes, your camera allows you to adapt to various shooting situations. Acquiring focus is an essential aspect of any composition. Having the right elements of your photo in focus can affect the way it appeals to the viewer immensely.
While focus itself is an important element no matter what, different shooting situations can definitely affect how easy it might be for you to focus properly.
For example, the zone focusing method might be the quickest way to establish the right depth of field and sharp focus in street photography. But in the context of a studio portrait, you would probably want a different approach to get that subject isolation and fine bokeh.
Camera focus modes can help you achieve these kinds of compositional goals. Remember: just because a focus mode might have “automatic” in its name that doesn’t mean that it is necessarily taking control away from you!
AF-S (Auto Focus Single Shot)
Single shot autofocus mode is one of the most commonly used focus modes in digital photography. It also tends to be the default AF mode on many entry-level and intermediate DSLRs and mirrorless cameras.
In autofocus single mode, your camera takes over focus control as soon as you press the shutter button halfway. Depending on lighting conditions, AF-S mode may “hunt” for a while before it establishes focus. With the right camera and lens, though, this should only be a rare occurrence.
With single shot autofocus active, your camera will lock you out of tripping the shutter before focus has been acquired. Normally, this means that you first need to prompt focus with a half press of the shutter button, wait for a focus lock, and then continue pressing the shutter button all the way to take the picture.
Using AE-Lock/AF-Lock to Focus and Recompose
However, you can also override this limitation by using the AE-Lock/AF-Lock button on the back of your camera. Not every DSLR or mirrorless camera will have this feature, so it is worth checking if your model does.
By pressing (usually holding) the AE-Lock/AF-Lock button, you prevent the autofocus mode from further trying to establish a focus lock. This enables you to take a picture at any moment.
This allows you to practice a technique called focus and recompose. To put it simply, you can engage the autofocus lock to focus on a subject outside of your AF Area.
Focus on the subject first, then use AF-Lock to keep the focus on the same point while you readjust the composition. Then you can fire the shutter without any obstruction, even if your subject ends up at the edges of the frame!
While this is not the kind of composition that many photographers will employ heavily, it is nonetheless a very creative method to know. AE-Lock/AF-Lock can definitely help you unlock complete control over your images beyond the limitations of how single shot autofocus works by default.
AF-C (Auto Focus Continuous)
Continuous focusing mode is a more advanced autofocus mode available on most modern digital cameras. In AF-C mode, autofocus will normally remain active for as long as the button remains under halfway pressure.
This is incredibly useful for tracking moving subjects. Instead of relying on a static, single point focus lock, AF-C lets your focus “travel” freely. You can trip the shutter at any moment you please by just pressing down on the button completely.
In this AF mode, using AE/AF Lock disengages further hunting for focus. Your camera will simply freeze the last focus point that was acquired. In wildlife photography, for example, this makes AF-C mode extremely versatile, capable of focusing on fast moving subjects easily but also relatively silently.
AF-A (Auto Focus Automatic)
Automatic autofocus mode, or AF-A, is a newer innovation intended to simplify and streamline the process of choosing between automatic focus modes. AF-A lets the camera decide which automatic focus to use, intelligently switching between single shot and continuous focusing mode as required.
If the subject moves, AF-A will engage continuous autofocus. Meanwhile, if the system detects that your camera is resting on a tripod and you are composing a stationary scene, AF-S mode will automatically activate instead.
This makes AF-A most useful when dealing with rather unpredictable conditions where even switching between a single shot and continuous focusing mode might risk losing a split-second frame.
On many modern mirrorless cameras and some DSLRs, AF-A is the default autofocus mode unless otherwise specified. On some others, you need to select AF-A by means of a switch located on the camera body or through internal menus.
Manual Focus Mode
Of course, nothing offers more direct, complete control over your exposure than switching to full manual focus mode. Learning to use manual focus well is an essential skill that marks a rite of passage for many young, budding photographers, and for a good reason.
In manual focus mode, there’s no need for advanced cameras with high-tech features like AE/AF-Lock, or automatic autofocus mode with its intelligent focus mode switching.
Instead, it is you, the photographer, who gets to fully determine the range, depth, and quality of focus in your image. Of course, this comes with a much more severe learning curve than many automatic modes.
Holding the manual focus ring on your lens barrel and rotating it to bring your subject into sharp focus sounds easy enough. But how your camera mechanically visualizes focus for you in manual mode differs greatly between brands and designs!
On most DSLRs, you will get relatively few manual focus aids apart from a light-up electronic rangefinder dot that lets you know when the subject in your viewfinder is tack sharp at the current distance. With a fast lens, even this tool will hardly be necessary. The optical viewfinder assures that you can observe the depth of field in real-time while you compose. Slower lenses, however, are notoriously difficult to focus on single-lens reflex cameras without some mechanical assistance.
Mirrorless cameras, meanwhile, tend to include a much higher variety of manual focus goodies.
Apart from observing your DOF live via the EVF, you may be able to rely on features such as focus peaking, which highlights your focus points visually by means of a live overlay.
Are Autofocus Modes Inherently Superior?
While some may get a kick out of bashing automatic or manual mode one way or the other, let me tell you here that such supremacist claims have no place in professional photography. True, autofocus presents plenty of advantages in speed and precision, especially in fields such as wildlife photography.
Likewise, the manual focus may give you a more precise depth of field control and better performance in low light conditions. Not to mention that it is perfectly silent – a trait especially useful for candid types of documentary photography.
However, the state of today’s advanced autofocus technology evens out the differences between different focus modes considerably. This makes the choice between manual focus and automatic modes more of an issue of technique and preference rather than performance.
Some may find it much quicker and more straightforward to use manual focus mode for nailing selective focus, bokeh, and background separation in fine art portraits, for example. Others will set up their own flow based on single shot autofocus combined with the focus and recompose technique for the same results.
And in the same vein, while some action photographers might master the use of their camera’s aperture and manual focus to get perfectly-sharp shots at high speed, others will find AF-S mode to be much more precise and reliable, requiring less effort to churn out well-exposed, crisp pictures.
AF Area Modes and Their Roles
When working with any automatic focus mode, one important element to manage is the autofocus area. When you focus manually, you set the distance to your subject via the ring on your lens barrel, adjusting back and forth to narrow down the depth of field and fine focus.
However, autofocus modes need to be approached differently. Instead of thinking in terms of subject distance, you manage the outcome of your shots by means of individual focus points distributed across an autofocus area.
The extent and location of this AF area lets your camera decide where exactly to focus on the subject within your frame, making it a very important aspect of working with different autofocus modes.
Let’s take a look at a few of the many AF area modes offered on modern digital cameras. Having so many options might seem a bit overwhelming to you as a beginner, but you may soon realize how much power and usability is contained within this selection of modes!
Single-Point AF Area Mode
This is the most basic autofocus area mode and in many cases, the default option. In this focus mode, you manually select one focus point near the center of your frame. Your camera will then use that single point as a reference for acquiring focus and assume that your subject remains within that small area.
While some cameras may only give you a dozen or fewer focus points to choose from, many offer more than 50, which can make single-point AF area mode quite versatile.
Because you need to manually switch between individual focus points though, this is far from the fastest mode you can get. Single point autofocus modes are mostly preferred by landscape photographers, portraitists, and others who deal with relatively static subjects.
In such scenarios, using this mode can give you the same kind of freedom over depth of field and subject acquisition as manual focus without the need for the focus and recompose technique.
Group AF Area Mode
This more advanced AF area mode is your best bet for keeping moving subjects tack sharp with minimal effort. In Group AF area mode, you find focus by selecting a whole group of focus points, hence the name.
Depending on the camera, you may be able to keep anywhere from three to six points active at the same time. This is generally more than enough to track one or multiple subjects on the move, making Group AF one of the preferred focusing modes among wildlife, documentary, and action photographers.
Dynamic AF Area Mode
If you require something even more advanced, look no further than dynamic area AF modes. Often referred to as Dynamic AF Area Mode, this autofocus area configuration allows you to select a single focus point for high precision. However, there’s a trick! Dynamic AF Area Mode automatically switches over to neighboring focus points in case your subject moves.
On most cameras, you should be able to select the extent of this dynamic area, i.e., the number of ‘dynamic’ focus points that your camera may intelligently switch between. A smaller area is good for predictable subjects moving in one consistent direction, as it improves precision at high speed.
However, a larger dynamic area can work wonders when dealing with skittish, fast, and chaotically moving subjects, such as flocks of birds, for instance.
Auto AF Area Mode
Finally, of course there is an automatic autofocus area mode for those who want their camera to take full control. In Auto AF Area mode, your camera’s maximum usable focus area is activated. The AF system intelligently chooses which focus points to use by continuously analyzing movement within the scene.
This mode can work great when you are not sure what working distance and what subject behavior you are going to face. Especially for beginners, Auto AF Area mode can minimize guesswork.
However, as you’re getting more serious about learning to control your camera’s various focus modes, you might find automatic AF area selection to be limiting. Any of the previous modes described in this section offer you greater, more precise control over which subject and what area to focus on.
Ultimately, this helps you realize the view of your photograph that you envision in your mind’s eye!
A Short Intro to Back Button Focus
On many digital cameras, pressing your shutter button halfway is not actually the only way to engage the specific focus mode you chose. A small button, usually labeled ‘AF-On’ and positioned next to the AE/AF-Lock switch, may be found on the back of your camera as well.
When this button is pressed fully, your choice of autofocus mode activates and locks on the target. Hence, using this button instead of the usual shutter button is called the back button focus.
Now, why would you use this alternative method? It’s simple: with different autofocus modes, especially continuous autofocus, it provides you with a more ergonomic and foolproof way of separating focus from composition. By dedicating the focus control to one button and shutter release to another, you can work in continuous focus mode just as in one shot AF, even applying some principles of the focus and recompose technique!
Note that even if your camera lacks a dedicated ‘AF-On’ focus button, you may still be able to reconfigure your controls to use back button focus via the menu system. Look up documentation on your camera model to see how this works in practice!
Finding the Right Focus Mode for the Job
As you have seen today, the variety of focus modes available on your camera are there for one reason: versatility. Offering you great power and flexible choices for nearly any kind of photo, mastering your automatic and manual focus modes is all about having the right tool for the picture you’re trying to take.
In that spirit, it’s important for you to know, practice, and understand the different focus modes that are most important for your kind of photography. It’s not worth stressing too much about mastering everything your camera has to offer – that’d be quite a lot and for a reason!
Rather, train yourself in the skillful use of the focus mode (or modes) most relevant to your work. In doing so, I’m sure you will find success.
Have fun shooting and until next time!