Photography – With exposure objective focusing means – focusing aid – or... – Dual purpose photoelement
Reexamination Certificate
2005-12-13
2005-12-13
Perkey, W. B. (Department: 2851)
Photography
With exposure objective focusing means, focusing aid, or...
Dual purpose photoelement
C396S111000, C396S121000, C396S148000, C396S271000, C348S341000, C348S345000
Reexamination Certificate
active
06975810
ABSTRACT:
A camera comprises a spatial modulation optical filter that is disposed in a viewfinder optical system for subject observation at or near a position optically equivalent to an estimated image forming plane of a photographic optical system and modulates a subject light flux entering via the photographic optical system with transmission characteristics to obtain a light flux having a predetermined spatial frequency; a photoelectric conversion device that outputs a signal corresponding to detected light; an optical element that guides the subject light flux having been modulated at the spatial modulation optical filter to the photoelectric conversion device; and a focal adjustment state calculation means that calculates a focal adjustment state of the photographic optical system based upon the signal output from the photoelectric conversion device having received the modulated subject light flux.
REFERENCES:
patent: 4441798 (1984-04-01), Watanabe et al.
patent: 4488799 (1984-12-01), Suzuki et al.
patent: 6226461 (2001-05-01), Homma et al.
patent: 6549730 (2003-04-01), Hamada
patent: 2005/0036779 (2005-02-01), Iwane
patent: A 2001-203915 (2001-07-01), None
Nikon Corporation
Oliff & Berridg,e PLC
Perkey W. B.
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