I know the zoom lenses 18-55mm XF and XF 10-24mm. My two copies work quietly and quickly and unobtrusively during AF. Due to the massive advertising for the XF 14mm as a reference product in terms of autofocus speed I meant that you can not go wrong with this lens. I was surprised then the volume of the lens and on the significant 'pump' to focus. In the near and in the far range, the pump was most pronounced and therefore the speed is not determined within the reference range of 0.08 seconds. But even at intermediate distances sometimes occurred a lightning-fast focus, then a short one-off pumps on. We tested the XF 14mm at an X-T1. I opted for the XF 10-24mm.
