Two-ring type filter set capable of independently driving an inner filter disposed at the rear side to rotate so as to adjust the dimming effect of the inner filter
TW201830116A
Two-ring filter assembly comprising a first ring body, a second ring body, a first lens, and a second lens and having no dirt entering the area between lenses
CN106814523A
Two ring type filter groups
TW201710771A
Bicyclic filter set
TW201701000A
Three-ring type filter set comprising a front retaining ring, a middle retaining ring and a rear retaining ring with each provided with corresponding guide inclined surfaces for easy assembly
