If you screw this lens ring on the lens, the lens cap does not fit mehr.Will you put the lid on the lens, the ring must first again be unscrewed. It is therefore easier and much cheaper to filter the same, so as usual, to screw into the lens. So seen an unnecessary invention. Unless you are happy when a 1500, - walks lens without lens protection, or one sets out to search for a suitable Lens cap. Above said is true for NIKON. Whether it is better in other camera manufacturers, I have not tried.