| ReturnTo Theme-Group-Choice | Onelevelup |
| 2H018 | Viewfinders | |
| G03B13/00 -13/28 | ||
| G03B13/00-13/20;13/24-13/28 | AA | AA00 VIEWFINDER APPARATUSES |
AA01 | AA02 | AA03 | AA04 | AA05 | AA06 | ||||
| . Direct-vision viewfinders | . . Use of lenses | . . . Inverse Galilean viewfinders | . . . Bright frame viewfinders | . . . Albada viewfinders | . . Indication of visual field frame | |||||||
| AA11 | AA12 | AA13 | ||||||||||
| . Reflex viewfinders | . . Twin-lens reflex finder | . . Viewfinder hoods | ||||||||||
| AA21 | AA22 | AA23 | AA24 | AA25 | AA26 | AA27 | AA28 | AA29 | AA30 | |||
| . . Single-lens reflex finder | . . . Reflecting surface of half-mirror | . . . Installation of pentaprism | . . . Arrangement of exposure meter | . . . Prevention of inverse incoming light | . . . Features of optical systems | . . . . Prisms | . . . . Pentaroof reflecting mirrors | . . . . Switching of eye level to waist level or vice versa | . . . . Partial enlargement of visual field | |||
| AA31 | AA32 | |||||||||||
| . VTR camera viewfinders | . . Electronic viewfinders | |||||||||||
| BA | BA00 VISUAL FIELD ADJUSTMENT |
BA01 | BA02 | BA03 | BA04 | BA05 | BA06 | BA07 | ||||
| . Correction by replacement of camera lense | . . Adjustment of lens system | . . Adjustment of visual field frame | . Correction of paralax from shooting too close | . . Adjustment of viewfinder installation position | . . Adjustment of visual field frame | . . Use of attachments | ||||||
| BB | BB00 DIOPTER ADJUSTMENT |
BB01 | BB02 | |||||||||
| . Adjustment of lens system | . Use of attachments | |||||||||||
| BC | BC00 VIEWFINDERS COMBINED WITH RANGE FINDERS |
BC01 | BC02 | BC03 | BC04 | BC05 | BC06 | BC07 | BC08 | |||
| . Autofocusing | . Overlapping double image type | . . Adjustment of mirror | . . Use of declined prism | . . Movement of intermediate lens | . Zone focus | . Pendulum focus | . Stereoscopic vision | |||||
| BD | BD00 RETICLES |
BD01 | BD02 | BD03 | BD04 | BD05 | BD06 | BD07 | BD08 | BD09 | BD10 | |
| . Structure | . . Glass fibers | . . Split-image prisms | . . Microprisms | . . Diffraction angle | . . Liquid crystal | . . Integrated with Fresnel lens | . . Photoelectric device for distance measurement | . Installation of reticle | . Manufacture of reticles | |||
| BE | BE00 OTHERS |
BE01 | BE02 | BE03 | BE04 | BE05 | BE06 | BE07 | ||||
| . Installation and support of viewfinder on camera | . Indications inside viewfinder | . Viewfinders of binocular type | . Viewfinders that can be stowed in the camera | . Replaceable viewfinders | . Water- and dust-proof viewfinders | . Prevention of ghosts and reflected light |