I bought several 52 mm diameter filters for a first fixed lens 50 mm. With a second objective of 18-105 mm, the diameter increased to 67 mm ... not bought the same filters, the ring fits perfectly to the thread of my mind, which allows me to use my old filters (polarizing and warm, studding or close-up +2, +4 particular) on my new goal. However, a very visible vignetting appear on the wide-angle focal lengths (18 to 25 mm approx.) Saw the ring occupies 1.2 mm on the periphery of the lens. This ring is therefore occasionally used according to specific needs, which is my case.