A new video shows the a9’s Eye AF (in AF-C) tracking working remarkably well with a single subject, tracking the subject’s eyes all the way to the edges of the frame. Here are three reasons we’re impressed, and a couple reasons we’re still left ambivalent:
Thumbs up:
- The a9 continues to track the subject’s eye when all it sees is his profile. It’s quite robust (though not robust enough; see ‘thumbs down’ below).
- It tracks the eye at 20 fps, while the a7R II’s Eye AF-C falls apart in continuous drive.
- When the subject turns his back to the camera, the camera doesn’t jump off to the background, maintaining focus at its current position instead.
Thumbs down:
- Sony continues to offer no dependable solution for when you have multiple subjects in the frame. Though you can use this workaround to select which subject you want the camera to target, it’s prone to erratically switch subjects. Here’s a far faster way to select the subject to target.
- When the subject in the video turns completely around, the camera stops tracking him altogether, unlike Canon Dual Pixel AF which uses enough ‘fuzzy logic’ to stay on our subject. Although we’re happy that in this example the camera doesn’t jump off to something else, if there were another face in the scene it likely would have.
Our request to Sony:
Be robust enough that when the camera no longer detects the eye of the original subject, focus just hangs around the general vicinity of the subject. This should be easy as the camera has distance (phase) information indicating the distance of the general subject matter around the eye its been tracking – but now lost – hasn’t radically changed.
Furthermore, retain some remembrance of the facial features when Eye AF is initiated so as to re-attain eye focus when the subject looks back at the camera and re-recognizes the initial eye (pattern) after having lost it. This is how Nikon’s 3D subject tracking works.
Articles: Digital Photography Review (dpreview.com)