Viewfinder mask orienting device in a camera
US4251149A · kind A · utility
8Cited by
3References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 2, 1979 |
| Grant date | Feb 17, 1981 |
| Priority date | — |
| Expiry date | Oct 2, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B13/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the viewfinder optical system of a reflex camera with a film holder which is rotatable to change the orientation of the oblong image on its film, a viewfinder mask orienting device supporting a square focusing screen has two pairs of rotatable masking blades, the two blades of each pair being integrally joined in Vee shape, which are actuated by the rotation of the film holder to operate cooperatively to alternately mask edge parts of the two pairs of opposed sides of the focusing screen thereby to form an oblong viewfinder image and change the orientation of this image to conform to that of the image on the film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.