Field frame for finder

摘要

A field frame for use with a finder which provides arbitrary or stepwise switches of an aspect ratio of the finder. The field frame is made up of a standard field frame, a first L-shaped field switch frame having a dowel pin and two elongated holes, and a second L-shaped field switch frame having a dowel pin and two elongated holes. These two L-shaped field switch frames are piled up one on top of the other in such a manner that dowel pins standing on the main body of the standard field frame fit into the laminated elongated holes of the L-shaped field switch frames. A driving wheel having engaging cutouts is also laminated on the L-shaped field switch frames so that the engaging cutouts can engage with the dowel pins of the field switch frames. The driving wheel is also provided with a lever. The clockwise rotation of the driving wheel causes the field switch frames to conceal the right and left edges of the standard field frame, whilst the counterclockwise rotation of the driving wheel causes the field switch frames to conceal the upper and lower edges of the standard field frame.