In no way am I affiliated with, or a fan of, Fujifilm's X series. At one time I thought I was. After three years in the X camp, I sold everything X I had: X-T1, X-Pro 1, X100s, and my lenses. I'm vocal about Fujifilm's design boners, including their penchant to Peter Keating anachronistic design for the sake of anachronism.
But credit belongs where it is due. And the X-T2, despite what its anachronism, tracks far better than the X-T1 with the same lens, at the same aperture, ISO, and under the same conditions. And, whilst tracking, its EVF barely blacks out at all. It also tracks more accurately than the Leica SL with the 24-90 Elmarit, a feat of which the X-T1 isn't capable.
Mea culpa: In 2013, I quit my job at an event studio in Chiba, Japan, to develop my macro still life studio. As such, I seldom shoot autofocus. When I do, I'm in dark Tokyo embassies, or at darker audiophile panels, whose subjects need AF about as much as fish needs a bicycle. Typically, my cameras (Sinar arTec, Linhof M679cs, Rollei X-ACT 2) sit atop camera stands, behind bellows, large format lenses, and rickety press shutters.
Exculpate moi: That said, I know improvement when I see it. And the X-T2's AF is demonstrably better than the X-T1's. Also demonstrably better are its sturdy new interface/data flaps, and top dials.
Coupled to the same 18-55 lens, it tracks along the z-axis far more reliably than the X-T1. The series of images below show were shot under Yodobashi Camera's flickering fluorescent lights at ISO values that Lightroom reads as 2500, an f-stop of f/5,6, and the lens set to 50mm -- two of which contradict what I purposely set: ISO 3200 and f/4,0. Whatever.
Note: the X-T2 was attached to three snake-like tethers: lock, battery, and USB, which restricted the smooth fall/drag z-axis approach to the flowers. Consequent to reaching the end of such a leash, the camera and I dipped from the third frame. Even so, the X-T2 chugged along, tracking stamen to petal as I stubbed my toe on the helpful sales clerk. Aside from the severe crop, no image has been sharpened, de-noised, saturated, constrastified, or smoothed over. The images I obtained from the X-T1 were unsharp and mashed. Ultimately, they disappeared when the helpful sales clerk formatted my card.
Lens: 18-55 f/2,8 - f/4,0
Action photographer: Nathan Wright
Action subject: a silk potted plant
Action motion: falling toward the subject whilst simultaneously mashing the shutter button (whose new, libidinous posture makes mashing easier than ever).
Consequence: mostly printable results for the effective AF target in all frames.
Comparison: the same 'test' performed on the X-T1 yielded a single in-focus frame along a similar drag.
There's hardly a test, let alone a reliably reproducible methodology in the above. I was at Yodobashi. I saw an X-T2 and X-T1 side by side. I had to touch both. Touch them I did. The sales clerk agreed with me that the X-T2 isn't up to high-end dSLR standards set by Nikon's D800 and beyond, but is one of the best in the mirrorless land. He also suggested that perhaps the Sony A6300 may track better, but neither of us laid bets.
The X-T2 feels better in the hand than the X-T1. It tracks better than the X-T1. It is built better, too. If the X-T1 was the alpha build, the X-T2 is the production version. I think that X fans will like it heaps.
ohm image: Fujifilm Australia: Are You Carrying Excess Camera Baggage?
ohm image: dSLR to mirrorless to SLR - one Man's Fujifilm conversion
ohm image: Panasonic GH4 meets Fujinon Digipower XA55
ohm image: Just how good are Fuji x @iso6400?
ohm image: ONE TENTH OF A SECOND
ohm image: X-T1 firmware 4.00 brings zone/wide focus tracking
ohm image: The Sony A7ii taught me to respect the Fujifilm X100s