In order to achieve good AF tracking results, I set the camera’s AF-C to “focus priority” (as opposed to “release priority”). Fuji’s PDAF loves vertical lines (or horizontal ones in portrait format), so it’s a bonus to offer the camera just that. Obviously, it’s essential to focus with one of the central nine AF frames. Wouldn’t it be nice to have a sensor that offered PDAF over the entire viewing area? Oh well, one can dream.
Back to reality: Even at 8 fps, the X-T1 still adapts the exposure between shots, but it won’t change white balance or dynamic range settings. If you want to keep the exposure constant throughout a high-speed series, I recommend shooting in manual mode.