When warm air touches cold glass, moisture in the air is condensed. Camera and binocular finders are no exception. In photographing at a cold place of ski or skate, the breathing of a cameraman or moisture transpired from his/her eyes dims the finder. For this reason, you cannot concentrate your attention on photographing or miss a decisive moment, and it was a troublesome problem for professional cameramen who are required to perform accurate photographing all the time. The anti-fogging eyepiece was developed to solve such problems. Subsequently, eyepieces for binoculars were also marketed and are demonstrating their effectiveness for bird watching, astronomical observation and other activities.