If you're an X100 owner, you'll be disheartened to hear that the X-Pro1's auto-focus system is not much faster or more accurate. When set in Multi-area AF, the X-Pro1 will consistently fail to acquire the right target, and even when it does it will take a second or so to achieve focus - it does this even when the target looks obvious. What this means is that you can essentially rule out shooting fast moving subjects with the camera, and in low-light AF speed and accuracy drop noticeably. To be fair, low-light auto-focus is something all mirrorless system cameras with their contrast detect AF systems struggle with, but the X-Pro1's AF is slower than the best of the current generation of mirrorless cameras.
The AF speed will compound with the longer lenses, the 35mm focuses slower than the 18mm and the 60mm will hunt the longest. It's simply maddening, as the slow AF has cost us more shots than we'd like – the best way to describe it is that the X-Pro1's AF response feels more like a digital compact camera's than a DSLR or contemporary mirrorless system camera.
If you decide to circumvent the sluggish Multi-AF mode with manual selection of AF points, the X-Pro1 doesn't make it easy. To open up AF selection, you have to first press the AF button, then select the AF point via the d-pad – and these controls are on the opposite ends of the camera! It takes a while to even get used to, and it means constant two-handed operation of the camera. The second or so it takes to do this also means that the X-Pro1 is unsuitable for quick shots where you only have that second to shoot. To Fujifilm's credit they've shifted the AF button down to the last button on the left row instead of the second place it was on the X100, making it easier to find by feel.
Manually selecting AF points in the optical viewfinder mode is even more challenging. Because the viewfinder is not aligned with the lens, neither is the focus point. The X-Pro1 tries to help by providing an approximate of the eventual focus point and framing, but only after you've selected it and not during.
Perhaps to compensate for the sluggish AF, the AF Lock button is situated on the thumb-rest within easy reach, which means you can set focus, re-compose and shoot. This is one way to work around the X-Pro1's slow AF, the other is to engage manual focusing via the focus mode switch beside the lens. Like the X100, manual focus is driven electronically. While the focus rings feel like they react more responsively than the X100 (which took ages to change focus manually) they're still slow. Manual focusing is not reflected in the optical viewfinder, you must switch to the electronic viewfinder or the back monitor in order to check focus. To check focus, you can press down on the command dial and the X-Pro1 will magnify into the focus point.
We had the unique opportunity to shoot with both the X-Pro1 and the new Olympus OM-D E-M5 at the same time, and the latter camera has solved the AF challenge in an elegant way. To manually dictate an AF point while in Multi-frame AF mode on the Olympus E-M5, you simply tap any direction on the d-pad and the camera will automatically open up AF point selection. To go back to Multi-area AF mode, drive the AF point beyond the edges of the selection points. It's fast and easy, a single-step action compared to the X-Pro's two steps.
Besides the user interface, Fujifilm could learn another valuable lesson from Olympus. Olympus' first two mirrorless system cameras, the PEN E-P1 and E-P2, also had sluggish AF systems. They pulled off an impressive overhaul with the E-P3 however, that camera (and now the E-M5) offers lighting quick and accurate AF, with the ability to detect and focus on faces and eyes.
Unfortunately, the X-Pro1's auto-focus system doesn't improve beyond the X100 and X10, and that's disappointing. Surprisingly, it seems that Fujifilm doesn't think their auto-focus systems need work – during our interview with the X-Pro1's product manager, Kawahara looked genuinely surprised to hear us say the X100's AF had problems (he also honestly seemed to like the single-function RAW button).