Unlike newer lenses with bayonet lock this Geli has to be screwed. That, in turn, that a filter (eg filters) must be screwed on the lens first, and only after that Geli. At DX this represents no problem with respect. Shadings represent. Only drawback is that Geli can be fitted for transporting not wrong as in newer lenses around. This circumstance was me though previously known but still annoying (ie Geli always off somewhere or plug). In addition, the mounting means of a bayonet is simply much more convenient than the screw. In the absence of a more practical alternative available here therefore "only" four stars.