Autofocus

The Olympus E-M1 Mark II comes with an entirely new autofocus system, featuring 121 on-sensor phase-detection points. The company is quick to point out that, during burst shooting, one of the two quad-core processors in the E-M1 II is devoted entirely to autofocus: actively analyzing the image just taken as well as the current state of the scene to help the camera continue to accurately track the subject for the next shot.

The E-M1 II is plenty capable of keeping up with moving subjects as they move across the frame - usually.
Olympus 40-150mm F2.8 Pro at 80mm, processed to taste using a beta version of Adobe Camera Raw. ISO 1000, 1/800 sec, F3.2. Photo by Carey Rose

All of that happens at a maximum rate of 18 frames per second when you use the electronic shutter. That's seriously fast, even when compared to flagship Canon and Nikon DSLRs, which top out at 14 and 12 fps respectively with continuous autofocus - but they both have flipping mirrors blocking the AF system, while the E-M1 II can use an electronic shutter to reduce blackout.

But the question remains - is this new autofocus system any good?

The setup

While Fujifilm's X-T2 adopted a Canon-style system of use-case based presets of three underlying autofocus parameters, Olympus on the surface appears has gone to almost a more Nikon-style system, offering relatively little in terms of customization. You still get all the autofocus modes from other Olympus cameras, with the most commonly used ones being S-AF for single-acquisition autofocus, C-AF for continuous autofocus for a given point or cluster of points (though, annoyingly, there is no AF Lock capability in continuous autofocus), and C-AF + Tracking for letting the camera do the tracking for you.

What's so 'Nikonian' about it is that the only variable you get to control is C-AF Lock, which ranges from +2 (Loose) to -2 (Tight), but as you can see in the below table, this setting i really controlling two variables. Until recently, Nikon cameras only offered you an option for 'Focus Tracking with Lock-On,' which told the camera how quickly to re-focus if an obstacle got between you and your subject. They've now added a second option to bias their system from 'Steady' to 'Erratic' subjects.

Subject Movement Direction Subject Movement Speed Elements other than the desired subject  Example C-AF lock Setting

Forward & Backward

Irregular

Less

Animals, Wild Birds, sports, kids

 +2 (Loose)

Fixed

Races / Vehicles

 +1

Vertical & Horizontal


Irregular

Animals, Wild Birds, sports, etc

 –1

More

Animals, Wild Birds, sports, etc

 –2 (Tight)

Confused yet? It's best not to think of '-2 to +2' as a scale, but rather think of each setting as a specific use case.

Olympus' 'Loose / Tight' system incorporates considerations of both the consistency of movement of a subject and how quickly the camera should refocus to a different depth, using just this one value. 

All of this background is important, because in practice, not only is the E-M1 Mark II Olympus' flagship machine intended to appeal to professional sports and action photographers just like the DSLR flagships, but the E-M1 Mark II's autofocus system behaves very similarly to that of Nikon's 3D Tracking in the D500 - all the while shooting many more frames per second.

It's not perfect, but the E-M1 II's autofocus system is the best we've seen from a mirrorless ILC.

The bike test

For most of the test, we left the camera set to +2 'Loose,' which is the most 'aggressive' option - the E-M1 II will always be looking to refocus as quickly as possible (with no risk of obstacles getting in the way), on a subject whose speed is possibly erratic. Eventually, though, we threw some more variables into the mix because it put up such a good display.

Let's start with single-point continuous autofocus:

Here, you can see at a burst rate of 18fps (e-shutter mode) with Continuous AF, the E-M1 II performs with a very, very good hit rate (some images are slightly soft, but we'd call them usable). Impressive, but where it gets really impressive is when you enable C-AF + Tracking:

Here, the E-M1 II puts up quite the show (despite the soft first image), exhibiting roughly 75% tracking accuracy at a very long focal length. This is something mirrorless cameras, especially those with contrast-detect only systems, generally struggle with. The camera would occasionally get fooled though, generally refocusing on an object in the background, and while it would sometimes reacquire focus on Richard before the end of the run, on other occasions it just wouldn't.

Despite this occasional back-focusing, we were still fairly impressed, and so we added another variable into the scene - our own Jeff Keller, innocent pedestrian bystander.

 Loose +2
 Tight  –2

Here, the camera continuously tracked Richard's position through Jeff, though for the time that Jeff was under the autofocus area, the camera refocused on him. As soon as he left, the E-M1 II had no problem reacquiring focus on Richard, and continuing on.

So, we changed the C-AF lock to '-2' or 'Tight.'

As we predicted, the E-M1 II did not refocus on Jeff, though as we were shooting, the AF area continued to predictively track where Richard was, even when he was completely blocked by Jeff - but unfortunately, as Jeff moves through the foreground, the E-M1 II's focus jumped to the background, and we ran out of rollover boxes before it reacquired Richard (it usually got there in the end).

While this behavior is somewhat similar to the 3D Tracking behavior we observed during the course of the Nikon D5 review, it's obviously not perfect - the camera would ideally have continued to predict Richard's relative distance from the camera or at least held where it was, instead of shooting off to the background, or at least reacquired him much faster when he was no longer obscured. Anyhow, let's take a look at the real world performance.

The Real World

Unfortunately, the occasional back-focusing we noted in the bike test is present in the real world as well. The system is perfectly capable of impressive results, but will unpredictably fail and focus on the background a disappointing proportion of the time (this is all in C-AF while shooting 18fps bursts). If, however, you end up using C-AF + Tracking for subject tracking and firing off single shots at a time for candid portraiture and the like you'll find that it works incredibly well.

For this shoot, the camera was in the exact same settings as our bike test - with a C-AF Lock setting of +2, or 'Loose.' The disappointing infinity-focus behavior is somewhat reminiscent of how, with Canon's iTR system, the camera would sometimes randomly rack focus near the minimum focus distance before reacquiring the subject again, or simply start tracking something else randomly in the scene. But that's not to say that this refocusing behavior always happens: C-AF + Tracking is capable of doing extremely well, as with the dog below. But there are also bursts where the camera, as with the frisbee match, focused on the background behind the dog seemingly without rhyme or reason.

In any case, if you can follow your subject with a single (or group) of AF points, as many professional sports shooters are wont to do, the E-M1 II's accuracy is incredible, and you've got a faster burst speed than any flagship DSLR. And, to be fair, if you're using subject tracking and it does fail, that initial acquisition time is often fast enough to allow you to reacquire your subject and keep on shooting.

So the story is this - if you can follow the action yourself, you'll likely be thrilled with the E-M1 II's performance. If you're looking for industry-leading subject tracking during bursts, it's not quite there. On the other hand, the subject tracking is so 'sticky' during live view that it's certainly handy for more casual shooting of single shots in succession, such as for candid portraiture or concerts.

For this shot, I used C-AF + Tracking, initiated tracking on the singer at right using the center point and a half-press of the shutter, and recomposed while the E-M1 II continued to track him until I fired off a shot. Olympus 75mm F1.8, straight-out-of-camera JPEG. ISO 2000, 1/400 sec, F2. Photo by Carey Rose

In any case, given Olympus' history of updating its cameras, we're quite hopeful. It certainly seems, to us, that there is much potential in the E-M1 II's tracking performance - something that perhaps future firmware updates could improve.