Do not try to blow dust off the front lens with a blower! Due to the gaps between the lens and the decorative ring (the brand of the lens is written on it), dust is blown into the lens! Behind the lens hood attachment ring there is another encircling gap, where not only dust climbs, but also a sheet of paper easily enters. After six months of use, I took it to a service center to clean it. I studied this lens with colleagues, the same trouble.