When you start looking into buying a new digital camera, it's easy to feel overwhelmed by the sheer volume of features and specifications on offer. Understanding the key ones will help you find the right camera for your style of photography.
One feature that experienced photographers take seriously is autofocus performance. But what exactly is it, why does it matter, and when might you want to use manual focus instead? Let's break it down.
What is Autofocus?
In every image there's a subject — one you'll want rendered in sharp focus. Focusing a camera lens involves physically shifting lens elements until the clearest image of your subject is achieved. These adjustments depend on the distance between your subject and the camera, and even the smallest shift can make a significant difference to sharpness.
Autofocus (AF) automates this process. The camera and lens work together to make these adjustments when you half-press the shutter release button, or when you press a dedicated back-button focus control.
Autofocus vs. Manual Focus: What's the Difference?
As the name suggests, manual focus requires you to physically adjust the focus of your lens — typically by turning a focus ring on the barrel — until your subject appears sharp. While autofocus handles this automatically, manual focus puts you in complete control of what's in focus and to what degree.
Autofocus is fast and reliable for most shooting situations. Manual focus, on the other hand, gives you creative precision — particularly useful in scenarios where the camera might struggle to determine exactly what you want sharp.
AF Systems, Points & Modes Explained
Many photographers are happy with a basic understanding of autofocus, but if you want to make more informed purchasing decisions, it helps to understand the common AF terminology:
- Contrast Detection AF — Simple and effective. The system looks for contrast at the edges of a subject and adjusts the focal point until contrast is at its sharpest.
- Phase Detection AF — Light coming off a subject is measured to determine distance, and the lens adjusts accordingly. Generally faster and more accurate than contrast detection, particularly for moving subjects. Most modern mirrorless cameras use on-sensor phase detection.
- Focus Points — These are the points within the frame where the camera can achieve focus. Modern cameras typically offer a large number of focus points — often covering the majority of the frame — making it easier to place focus exactly where you need it. Cross-type points provide the most accurate autofocus performance.
- Single AF (AF-S / One-Shot) — The lens focuses once when you press the shutter, then locks. Best for stationary subjects.
- Continuous AF (AF-C / AI Servo) — The camera continuously adjusts focus as a subject moves. Essential for action, sports, and wildlife photography.
Why Would Anyone Use Manual Focus?
While autofocus is fast and accurate in most conditions, there are situations where manual focus is the better choice:
- Low light conditions — In dim environments, autofocus systems can hunt and struggle to lock on. Your eye will often do a better job of determining what's sharp.
- Macro photography — At very close focusing distances, depth of field becomes extremely shallow. Even a tiny shift in focus can dramatically change the result, and manual focus gives you the precision to place focus exactly where you want it.
- Creative control — Sometimes you want to focus on something the camera wouldn't naturally prioritise — manual focus lets you make that call.
Find the Right Camera at Ted's
Whether you're after a camera with class-leading autofocus for action and sport, or a system that gives you full manual control for creative work, our knowledgeable in-store staff are happy to help you find the right fit. Explore our full range of cameras and lenses at www.teds.com.au, or visit your nearest Ted's Cameras store.