I bought this lens and lo and behold it also had the loose aperture ring! Very disappointing. But I sent it into Fuji's repair center in Edison, NJ and they adjusted the ring tension. It's still not as tight as the 18mm lens, but now it's much better. This lens is amazingly sharp and straight. I cannot believe vignetting at low apertures is considered a defect in this day and age. It's the simplest thing to remove if that's not your thing. Me, I love it and mostly shoot wide open with my pictures.