Eye AF is an extraordinarily useful technology that can help ensure your subject’s eyes are perfectly in focus when shooting portraits.
Eye Autofocus (Eye AF) is undoubtedly on the list of groundbreaking autofocus developments in the past decade. Designed initially for portrait photography, it tracks and nails focus on the subject’s eyes consistently. Eye Autofocus has seen significant improvements and adoption across much of the photo industry, and photographing humans (and certain animals) has become much easier with it. Almost all recent mirrorless cameras contain some form of Eye Autofocus. Despite its advancements, this technology still isn’t 100% accurate, so here’s how to make the most of Eye AF in your camera.
The Lighting

Cameras and autofocus have jumped ahead by a leap year from what they used to be, but they can still only do so much. Your best bet to get great accuracy and precision is to give your subject more light. We liken autofocus to a typical outdoor plant. Give it more light and it will flourish and bear fruit. Give it less light, and it will shrivel.
The available light in your scene has a significant impact on your camera’s Eye AF performance. For Eye Autofocus to function properly, your subject’s eyes must first be visible. Obviously, it can’t focus on what it can’t see. This goes for scenes that are too dark as well as backlit scenes that are too bright. Give your camera a break; have your subject face towards the light so that their eyes become visible. For the best results, use a strobe or a flash with a modeling light. If you’re using ambient light in the field, try working with a street light, lights from a store, etc. If you’re not photographing in the city, consider using your camera’s AF illumination lamp. Most photographers turn it off by default, but it has its uses.
Tracking

Tracking with Eye AF is super important. If you’re shooting candid moments or street photography, it’s incredibly handy. But models typically change a pose after each shot. When they move, the camera’s Eye AF setting will track them. Consider setting your camera’s Eye AF focusing mode to continuous or tracking autofocus. Both modes play very well with Eye Autofocus and can have a dramatic effect on your hit rate. Be sure to give these autofocus modes a try in conjunction with your camera’s Eye AF system.
“Now, with the advent of Eye AF, getting the focus right every time has been made easier. You would think that a feature as incredible as Eye AF would be found only on higher-end cameras, but you would be wrong.”
Portraits: 9 Mirrorless Cameras with Eye AF That Nail the Shot Every Time
Touch It Up

Eyeglasses are the arch-nemesis to Eye Autofocus. Depending on the shape of the eyeglass frames, they can sometimes throw off Eye AF algorithms. Reflections that appear on eyeglass lenses can also obstruct the eyes. Using autofocus modes that allow for manual focus override can be super helpful in these conditions. The combination of manual focus and Eye Autofocus will get your focus mostly there. When you’re slightly off the mark, you can easily fine-tune the focus manually. Unless you absolutely must shoot wide open, consider stopping the lens down a bit to increase the depth of field, and more of your subject will be in focus.