I used this lens on a paid gig and halfway through the lens stopped communicating with the camera. I could not change aperture and there is no manual ring. I rebooted the camera (a6600) but it still did it. I turned it off again, took the lens off and rebooted. This time it worked...for a bit then it happened again. I then threw it in my bag and put on my 18-105. I will never trust another Samyang product based on this experience.