Trentside

Hi As Greybeard has commented, I am sure that this is normal. I have the 80mm macro lens which also has a linear motor and, when the camera is switched off or the lens is removed, it exhibits the same symptoms you describe. Once switched on the internal mechanism engages the 'floating lens group' and the 'clunking' disappears. The 50-140mm zoom is similar although perhaps not so obvious. I hope that this helps.