Autofocus

The face and eye detect algorithm has been updated in the E-M1 III and depending on the lens used, you can expect good precision and reliability when using this feature.
ISO 200 | 1/320 sec |F1.2 | Olympus 45mm F1.2

When it comes to AF, the E-M1 III is good at some things and struggles with others. When used in a traditional manner, where you manually keep an AF point or zone over your subject, it tends to perform well. And an updated face and eye detect algorithm makes it easy to capture sharp images of fellow humans without much trouble. But subject tracking performance lags behind the competition.

Key Takeaways:

  • Continuous AF can be tuned to be pretty effective if you can keep your camera pointed at your subject
  • Face and eye detect work well and it's easy to jump between subjects using the AF joystick
  • Subject Tracking AF tends to be poor at following its target but increasing C-AF sensitivity may improve hit rate for some subjects
  • Fn lever allows for quick changing between AF modes and areas, but does not remember face / eye detection or focus limiter settings

In depth

The E-M1 III uses the same AF system as its predecessor, with 121 on-sensor phase detect points, but with improved face and eye detection. The menu contains ample customizable AF options, identical to those offered in the E-M5 III. Some of these options , like 'C-AF Center Start' and 'C-AF Center Priority' seem intended for those who like to photograph fast-moving subjects in motion.

As on the E-M5 III, you can now assign the camera's rear Fn lever to toggle between two pre-chosen focus modes, including MF. Unfortunately, you can only save those top level AF modes, not more subtle AF settings like whether Facer detect is on/off or the focus limiter is in use. But you can now assign face detection to be toggled on and off with a custom button.

Autofocus performance

Our standard continuous AF test comes in two parts: the first tests the camera's ability to assess and predict the distance to an approaching subject, the second uses the camera's subject tracking mode, in which the camera also needs to recognize the subject and decide which AF point to use, to follow a subject approaching in an unpredictable manner.

The E-M1 III did reasonably well in the first half of the test. A single, central AF point was used, along with the 10 fps Continuous L drive setting (focus is locked in the higher-speed Cont H mode), using the mechanical shutter (you can expect similar results with e-shutter in Continuous L at 18 fps). We used the m.Zuiko 40-150mm F2.8 PRO for this test.

Set to its default 'C-AF Sensitivity' setting the E-M1 Mark III does a good job, especially a short while into the run. However, looking more closely we found the camera would continue to drop out of focus. The camera appears to take around 20 shots (approx 2 seconds) to fully recognize and respond to the behavior of the target.

Even shooting sequences with the bike already moving at a steady speed (to rule-out acceleration as the cause), there continued to be a period during which the camera hunts. In every run there would be some shots in which the camera drove the focus further away, which suggests it was struggling to understand the behavior of the approaching subject. However, these shots tend not to be too severely misfocused, so need not be cause for too much concern.

Subject tracking

Subject tracking was notably less successful. With default settings the camera would almost immediately ignore the subject and instead revert to its original position. It would then briefly re-focus when the subject crossed under the AF point, only to then refocus to the background. Changing the C-AF Sensitivity to 2 (the most responsive to unpredictable movement) and giving the camera a different colored target to follow produced much better results but only when both factors were combined (neither the more distinct target nor the increased sensitivity worked in isolation).

Checked shirt 'Sensitivity' +2
Distinctly-colored target and 'Sensitivity' +2

Based on these results, we would not advise using the AF Tracking mode for anything more than setting the focus point before carefully recomposing: it cannot be relied upon for moving subjects.

Face Detection

Olympus was the first brand to introduce eye detection AF and its latest implementation, with phase detection, appears to work well. It's quick at detecting faces and eyes and, in our experience, maintains focus on them well. It will continue to recognize a face even in profile.

However, there is no system to switch to non-face tracking if your subject turns away completely or briefly can't be recognized as a face. In that situation, there's a risk of the camera refocusing on other faces in the scene.

In our test the camera performed very well but the results appear to be somewhat lens dependent. The camera keeps the lens aperture wide open when focusing, which means the focus performance in low light depends on the maximum aperture of the lens. We found the camera could recognize a face when using an F2.8 lens, but would often focus in the middle of that face. With an F1.2 lens mounted, the camera had enough light to find the subject's eye on most occasions, even when shooting at F2.8.

Overall

Overall, the best results can be had by exploiting the camera's fast EVF and trying to pan to keep a fixed AF point or zone over your subject. Despite advancements in AF tracking technology across the industry, this is still the way that some pro sports photographers continue to work. Even then, and with the camera set to respond to the subject's movement, we'd still expect a few misfocused shots in the middle of most bursts.

For birding, where a subject may be static in a tree, or flying perpendicular to the camera (and hence not moving much in depth), the camera can perform well. However, we did occasionally encounter the hunting behavior, especially if birds flew in front of something more complex than open sky.