One-Shot vs AI-Servo: Which Autofocus Setting Should You Use?

One-Shot versus AI-Servo: Which Autofocus Environment Should You Use?

One-Shot vs AI-Servo

If you’re just getting familiar with your camera autofocus settings , you’ve likely encountered the big question:

In the event you shoot with One-Shot AF? Or should you use AI-Servo AF? (Some cameras also offer a third option, called AI Focus, but it doesn’t work effectively and so I recommend you disregard it completely. )

Unfortunately, there’s zero easy answer, because One-Shot and AI-Servo are  both  useful with respect to the type of photos you capture.

So in this article, I’ll explain everything you need to know about these two autofocus modes. Through the time you’re done, you will know which option meets your requirements and how you can use it for amazing images.

Let’s dive right in, starting with the basics:

What is One-Shot AF?

One-Shot AF is the most commonly used autofocus method and is likely the default establishing on your camera. (Note: Upon many non-Canon cameras, it is known as AF-S. )

When you half-press your shutter button, the digital camera sets focus once (hence the term “one-shot”) and holds that focus until the image is taken.

As you can imagine, this is hugely useful if you want to focus then recompose . You are able to focus on one subject, then maintain focus while modifying your composition to include other elements. For instance, if you’re shooting a tree next to a fountain, you could set focus on the tree, then openly move your camera towards the fountain to create the best possible composition – while the concentrate stays locked on the forest.

On the other hand, One-Shot AF isn’t so great if you’re trying to track moving subjects. Lock focus on a motor cyclist riding toward you, and the focus will remain secured on the original spot, even as the biker zooms forward. Pretty soon, your subject is going to be out of focus, and you’ll be forced to lock focus again and again as the biker changes position.

baby in a basket with One-Shot autofocus

For this image of my week-old child, I used One-Shot AF. I half-pressed the shutter to focus on his body, after that adjusted my composition while keeping the focus locked.

What is AI-Servo AF?

AI-Servo AF monitors moving subjects. You half-press the shutter button to tell your zoom lens to start focusing – after that, if the area under your point of focus changes, your lens refocuses continuously before you take the photo.

(On non-Canon cameras, this autofocus mode is often referred to as AF-C. )

AI-Servo is perfect for scenes along with moving subjects. Bringing back again the biker example previously mentioned, if you placed your AF point over the biker plus half-pressed the shutter switch as she rode forwards, the autofocus would do its best to keep  the motor cyclist in focus.

Unfortunately, AI-Servo isn’t flawless; sometimes, if your subject is usually moving quickly, the focus will certainly lag behind and you will end up with slightly out-of-focus images. Or if your subject moves out from under your autofocus point (and you’re not with a couple form of broad AF tracking), the AF will concentrate on the background instead.

But AI-Servo is  certainly better for moving subjects compared to One-Shot AF, which regularly focuses behind the subject.

Make sense?

planes taking off with AI-Servo autofocus

For this shot of two Blue Angels taking off, We used AI-Servo; otherwise, I actually would’ve failed to track both of these jets as they moved.

When in the event you use One-Shot AF?

One-Shot AF will be the way to go when focusing on still subjects, such as landscapes, still lifes, some portraits (assuming your subject isn’t bouncing around, running, or dancing), and flowers. Here’s an even more complete list of genres that will rely heavily on One-Shot autofocus:

  • Landscape photography
  • Architectural photography
  • Cityscape photography
  • Still life photography
  • Macro photography
  • Food photography

Of course , you will have times when you’ll want to change over to AI-Servo AF – for instance, if your macro scene includes a fast-moving dragonfly – but for the most part, you may use this list to guide your own decisions.

Plus here’s a list of genres involving One-Shot AF  some  of the time:

  • Portrait photography
  • Street photography

For portrait photography, you must consider the kind of photos you’re taking. Considering doing a fast-paced portrait program with a lot of movement? Or will your subject be sitting or standing in place? For still subjects, One-Shot AF is a good idea, but for relocating subjects, go with AI-Servo.

As for street digital photography, some shooters use One-Shot AF to prefocus in specific points then wait around until a subject walks to the scene. Other photographers use AI-Servo AF constantly plus snap images as people today move toward them. Everything depends on your style!

When should you use AI-Servo AF?

Use AI-Servo AF whenever your issue is moving (especially if you’re working with a shallow depth of industry ).

So if you’re shooting sports activities players in action, birds in flight, or cars on the move, you should definitely use AI-Servo nearly all the time.

Here’s a list of photography makes that rely heavily upon AI-Servo autofocus:

  • Bird photography
  • Wildlife photography
  • Sports photography
  • Car photography
  • Wedding/event photography
  • Underwater photography

If you’re taking photos of birds, for instance, unless you notice an obvious reason to switch in order to One-Shot AF, I’d suggest you set your camera to AI-Servo AF and keep it there.

Which autofocus mode is best?

As I mentioned at the outset of this article, such a question does not have any real answer. In some situations, One-Shot AF is the best option, but in other situations, you will want to use AI-Servo AF.

In fact , there are even times when  manual  focus is the better bet. If you’re doing high magnifying macro photography or you’re shooting in the dark, your lens will likely fail to autofocus, so manual focus will be your only good option.

I do have a personal suggestion, though, and it’s the things i use for most of my photos:

Make use of AI-Servo…

…but not with the normal half-press focusing method.

You see, most cameras allow you to set your focus via a button on the  back  of your digital camera, which gives rise to a method called back-button focusing .

When combined with AI-Servo AF, back-button focusing gives you the best of both worlds. Here’s how it works:

Start by programming a button on the back of your camera to autofocus when pressed (and make certain AI-Servo is activated). Then simply, when you hold down the specific back button, your digital camera will focus continuously, just like if you half-pressed the shutter button.

When you let go of the back button, centering will lock. You can recompose all you like, you can take shots with the shutter button, etc ., without worrying about losing focus as you shift your AF point.

If you have a biker riding towards you, simply keep the back again AF button held down. Then, if the biker halts and you want to position them in the corner of the frame, you can let go of the back button and change your composition – whilst your focus remains locked in place.

Thanks to its versatility, I use back-button AF 90% of the time. It’ll save you plenty of headache seeking to switch back and forth between AI-Servo AF and One-Shot AF!

One-Shot vs AI-Servo: final words

Hopefully, you now understand whether to use One-Shot AF or AI-Servo (and you’ve hopefully furthermore been influenced to try out back-button focus). Learn to master your camera’s autofocus capabilities, and you’ll end up being unstoppable!

Right now over to you:

What do you think of these two concentrating modes? Which do you plan to use in your photography? Do you consider you’ll try back-button concentrating? Share your thoughts in the feedback below!

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James Brandon

James Brandon

is a scenery photographer and educator moving into Dallas, Texas. Join 20, 000+ photographers and get access to his free video tutorial library at his website . James also has an online store full of video courses, ebooks, presets and more. Use the coupon code “DPS25” for an exclusive discount!

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