Autofocus

The X-T100 shares its 91-point hybrid autofocus system with the entry-level X-A5. There are 35 phase-detect points that cover roughly 40% of the frame - this coverage lags behind some competing mirrorless cameras, but is likely on par or better than competing DSLRs when shooting through their optical viewfinders. The three available focus modes are single-point (where the focus point is adjustable), zone and wide/tracking. You can select an AF mode on its own or use the 'all' mode to let you switch between the three using the rear dial.

Key takeaways:

  • The X-T100 performs poorly at subject and depth tracking, with hit rates well below its peers
  • The X-T100 has a 91-point autofocus system, with 35 phase-detect points in and around the center of the frame
  • Face detection is laggy, and we recommend placing a single autofocus point manually over your subject for faster and more accurate operation
  • The phase-detect coverage of 40% is on the small size compared to mirrorless competition from Canon and Sony.

AF performance

First let's evaluate how the X-T100 can detect the distance of an approaching subject and drive the lens to that location. For this we use a single-point with continuous autofocus and shoot at 6 fps using Fujifilm's 40-150mm F2.8 lens.

Normally, modern cameras very perform well with approaching subjects, but that's not the case with the X-T100. The Canon EOS M50, one of the X-T100's closest competitors, had a nearly perfect hit rate. Sharp photos like the one below occurred roughly 50% of the time on the X-T100.

One of the 'hits' on the X-T100's straight-on focus test

The way in which the X-T100 handled the straight-on test does not bode well for how it will perform when our subject is moving randomly. The straight-on test illustrated that the camera either could not confirm the focus distance or drive the lens to that position. Since it can't do that, there's no way it will be able to handle movement along other axes, as well.

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The X-T100 struggles mightily in this test, with a hit rate of around 20%. The camera gets the subject in focus for a frame or two then immediately goes way out of focus. In some cases in which the subject was in focus, the selected point was where he was in the previous frame, so the results are probably luck. Even when the subject is in the phase detection area around the center of the frame, the result is out of focus, which isn't what we'd expect.

Low light AF

For our low light autofocus exercise, we used the X-T100 with a 23mm F2 lens wide-open in the sort of lighting you might find in a dim restaurant or bar. Take a look at the video and the sample images to see how the X-T100 fared when using face detection in this scene.

As shown in the video, the Fujifilm does a pretty good job of tracking Dan's face despite the challenging lighting. You'll also notice that, even when his face is in the central portion of the frame with phase detection points, the X-T100 will only use contrast-detect autofocus when using face detection. This results in a noticeable lag between the time you hit the shutter and the moment a photo is captured. Compounding this issue is the fact that even though the camera does eventually fire, sometimes the image will still be out of focus.

As with many older Fujifilm models, we recommend sticking to using a single point of your choosing, and manually placing it over your subject to ensure faster autofocus performance and greater autofocus accuracy.

Sample photoSample photoSample photoSample photoSample photo

To broadly sum up, we find that the X-T100's autofocus system is not up to the task of handling moving subjects, even when tracking an approaching subject, which is relatively easy for many competitive modern cameras.