Photography – Exposure control circuit – Override control
Reexamination Certificate
1999-07-06
2001-05-29
Perkey, W. B. (Department: 2851)
Photography
Exposure control circuit
Override control
C396S238000, C396S299000
Reexamination Certificate
active
06240256
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an exposure compensation device for an auto exposure camera, and in particular, relates to an exposure compensation device which automatically sets the lens aperture and the shutter speed to appropriate values through photometry.
2. Description of the Related Art
The selection of a proper aperture value is important for obtaining satisfactory pictures with an optical camera. Automatic exposure control devices are known for use in optical cameras. In general, known automatic exposure control devices select an appropriate aperture value and a shutter speed using calculations based on a film speed and photometry results.
However, to take pictures at under-exposure or over-exposure conditions, producing a desired result requires a certain degree of freedom. Thus, it is necessary to perform an exposure compensation operation. There are various proposals for methods of setting an exposure compensation amount with respect to an appropriate exposure value, as computed by the camera, using a separate independent exposure compensation device. In general, the known methods are directed toward two specific cases. In the first case, a fixed exposure compensation amount is needed for all pictures taken on a specified film, in the second case, various changes are needed in the calculated exposure compensation amount, such as when calculating the appropriate exposure value is a problem in normal automatic exposure, regardless of the film being used.
Conventional methods of setting an exposure compensation amount allow an exposure compensation amount to be selected by operating an independently attached operation button or rotating a dial on which exposure compensation amounts are identified. In these known methods, not only are special operation buttons necessary, but the operations are complicated and time consuming, which increases the likelihood of missing photo opportunities.
Moreover, there are problems associated with compensating the exposure by a fixed amount for an entire roll of film. For example, even if a picture is taken in which the exposure compensation amount is changed for a single roll, there is a danger that the photographer may forget to cancel the exposure compensation setting for the next roll. In conventional cameras, a display of the exposure compensation amount is only performed as an exposure compensation button is being pushed. Further, known exposure compensation devices typically only display a cryptic mark indicating an exposure compensation operation.
Another problem in setting the exposure compensation amount is that the automatic exposure mode of the camera, for example, a program mode, a shutter priority mode and an aperture priority mode, changes the exposure compensation operating procedure of the camera. That is, it is necessary to consider the exposure compensation operating procedure in the respective automatic exposure modes when setting the exposure compensation amount.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an inexpensive exposure compensation device for a camera having a plurality of automatic exposure modes that simply and appropriately performs setting of an exposure compensation amount without the need for special setting members.
It is another object of the invention to provide an exposure compensation device for an automatic exposure camera that displays the exposure compensation amount for a specified period when the exposure compensation amount has been set by an exposure information setting unit, such as an aperture value setting unit or a shutter speed setting unit.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
Objects of the present invention are achieved in an exposure compensation device for a camera having an aperture priority mode, the exposure compensation device comprising a first setting unit which sets the lens aperture, a second setting unit which sets a shutter speed, the second setting unit sets an exposure compensation amount when the camera is in the aperture priority mode, a photometric unit which performs photometry and outputs a photometric value, a photographic control unit which controls an aperture value and a shutter speed based on the photometric value, and an exposure compensation amount setting unit that changes one of the shutter speed and the aperture value according to the exposure compensation amount and performs exposure compensation based on the exposure compensation amount when exposure compensation is desired.
Objects of the present invention are also achieved in an exposure compensation device for a camera having a first and a second automatic exposure mode, the exposure compensation device comprising a first setting unit which sets the lens aperture, a second setting unit which sets a shutter speed, the second setting unit setting an exposure compensation amount when the camera is in the first automatic exposure mode, a photometric unit which performs photometry and outputs a photometric value, a photographic control unit which controls an aperture value and a shutter speed based on the photometric value, and an exposure compensation amount setting unit that changes one of the shutter speed and the aperture value according to the exposure compensation amount and performs exposure compensation based on the exposure compensation amount when exposure compensation is desired.
Objects of the present invention are further achieved in an input device for inputting different types of data into a camera, the input device comprising a setting dial for setting data, and at least one button for changing the type of data set by the setting dial.
Objects of the present invention are also achieved in an exposure compensation device for an automatic exposure camera equipped with a first setting unit for setting the lens aperture, a second setting unit for setting the camera's shutter speed, a photometric unit, a photographic control unit for controlling the aperture value and the shutter speed based on a photometric value obtained through the photometric unit, and an exposure compensation amount setting unit for changing the shutter speed or the aperture value during picture taking according to the exposure compensation operation and setting the exposure compensation amount when exposure is to be compensated.
Objects of the present invention are also achieved in an exposure compensation device for an automatic exposure camera that sets the exposure compensation amount with a shutter speed setting dial during the automatic exposure mode in which an aperture priority mode is given priority, or which sets the exposure compensation amount with an aperture value setting member during the automatic exposure mode in which a shutter speed priority mode is given priority.
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Hozumi Toshiaki
Ogawa Hidehiro
Nikon Corporation
Perkey W. B.
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