A camera filter unit (10) includes a front ring (4) for holding a polarization filter (2) and a rear ring (5) for rotatably holding the front ring (4). The front ring (4) includes a rear annular wall portion (18) extending in a radial direction (R), a rear annular plate portion (19) extending rearward from the inner peripheral end of the rear annular wall portion (18), and an annular projection portion (20) projecting for a short distance from the rear end of the rear annular plate portion (19) toward the outer peripheral side. The rear annular wall portion (18), the rear annular plate portion (19), and the annular projection portion (20) form an annular recess (21) on the outer peripheral surface of the front ring (4). The rear ring (5) includes an annular protrusion (45) protruding to the inner peripheral side. The annular protrusion (45) is inserted into the annular recess (21) of the front ring (4).
This filter frame (10) for a camera has: a front-side ring (4) for holding a first polarization filter (2) on the inner peripheral side thereof; a rear-side ring (5) disposed concentrically and behind the front-side ring (4), and capable of rotatably holding the front-side ring (4); and a rotation angle range-regulating mechanism (58) for regulating the angular range for the relative rotation of the front-side ring (4) and the rear-side ring (5). The rotation angle range-regulating mechanism (58) is provided with: a protruding portion (16) provided on the rear-facing annular surface (33) of the front-side ring (4); and a circular arc groove (17) which is provided in the front-facing annular surface (56) of the rear-side ring (5), and into which the protruding portion (16) is inserted. When the protruding portion (16) is positioned at an end of the circular arc groove (17), the relative rotational angle position of the front-side ring (4) and the rear-side ring (5) can be regulated.
A camera filter unit (10) includes a front ring (4) for holding a polarization filter (2) and a rear ring (5) for rotatably holding the front ring (4). The front ring (4) includes a rear annular wall portion (18) extending in a radial direction (R), a rear annular plate portion (19) extending rearward from the inner peripheral end of the rear annular wall portion (18), and an annular projection portion (20) projecting for a short distance from the rear end of the rear annular plate portion (19) toward the outer peripheral side. The rear annular wall portion (18), the rear annular plate portion (19), and the annular projection portion (20) form an annular recess (21) on the outer peripheral surface of the front ring (4). The rear ring (5) includes an annular protrusion (45) protruding to the inner peripheral side. The annular protrusion (45) is inserted into the annular recess (21) of the front ring (4).
A camera filter frame (10) includes a front ring (4) for holding a polarization filter (2) and a rear ring (5) for rotatably holding the front ring (4). The front ring (4) includes a rear annular wall portion (18) extending in a radial direction (R), a rear annular plate portion (19) extending rearward from the inner peripheral end of the rear annular wall portion (18), and an annular projection portion (20) projecting in an outer peripheral direction for a short distance from the rear end of the rear annular plate portion (19). The rear annular wall portion (18), the rear annular plate portion (19), and the annular projection portion (20) form an annular recess (21) on the outer peripheral surface of the front ring (4). The rear ring (5) is provided with an annular protrusion (45) protruding in an inner peripheral direction. The annular protrusion (45) is inserted in the annular recess (21) of the front ring (4).
A camera filter unit (1) includes an optical filter (2), a filter holding ring (3), and a filter frame (4) that are coaxially disposed in this order from the inside to the outside. The optical filter (2) has a tapered annular chamfered surface (13) on an outer peripheral edge of a rear filter surface (12). The filter holding ring (3) includes a front stopper (21) that is abuttable on the optical filter (2) from a front (X1) and a rear stopper (22) that extends along the annular chamfered surface (13). The filter frame (4) includes a second rear stopper (32) that prevents the optical filter (2) from moving to a rear (X2). The optical filter (2) is held by the filter holding ring (3) in a rotatable manner about an axis L. The optical filter (2) is fixed in a relatively unrotatable manner by the second rear stopper (32) abutting on the rear filter surface (12).
This filter unit (1) for a camera comprises an optical filter (2), a filter-holding ring (3), and a filter frame (4), arranged concentrically in that order from inside to outside. The optical filter (2) has a tapered ring-shaped chamfer surface (13) at the outer edge of the rear filter surface (12) thereof. The filter-holding ring (3) is provided with a front stopper (21), said front stopper (21) being capable of contacting the optical filter (2) from the front (X1), and a rear stopper (22) that extends along the aforementioned ring-shaped chamfer surface (13). The filter frame (4) is provided with a second rear stopper (32) that prevents the optical filter (2) from moving rearwards (X2). The optical filter (2) is held by the filter-holding ring (3) so as to be able to rotate about an axis (L), and the second rear stopper (32) contacts the rear filter surface (12) of the optical filter (2) so as to fix the optical filter (2) in place, preventing relative rotation.
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