| 摘要 |
This invention relates to large, ie view-cameras and supplants the fixed conventional viewing screen by using instead a focusing frame partly or totally geometrically congruent with the sheetfilm holder for such a camera, said frame being temporarily inserted into this camera for focusing, the conventional sheetfilm-holder partition being replaced in the focusing frame of the invention by a transparent viewing screen of which the focusing surface faces the lens. In this manner the invention achieves coincidence, within a desired and optionally zero tolerance, of film emulsion plane and focusing surface and eliminates the errors related to uncertain positioning of the conventional viewing screen of a large-format camera.
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