US 8,947,586 B2Granted

Diaphragm control apparatus of interchangeable lens camera

AssigneePentax Ricoh Imaging Company, Ltd.

InventorToshiaki Yamada

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Abstract

A diaphragm control apparatus of an interchangeable lens camera includes a photographing lens, a diaphragm control slider which is driven between first and second control ends corresponding to maximum and minimum apertures, a position detector, and a controller which drives the diaphragm control slider toward the first control end at high-speed, stores in a memory, as a temporary origin, a position to which the diaphragm control slider has rebounded after reaching the first control end. Thereafter, the controller compares the current position of the diaphragm control slider with the temporary origin while driving the diaphragm control slider at a low-speed towards the first control end. When the current position is within a predetermined range of the temporary origin, the controller determines the current position as the origin of the diaphragm control slider.

Claims17

Dependent claims

A diaphragm control apparatus of an interchangeable lens camera, comprising:

a photographing lens provided with an adjustable diaphragm device, in which an aperture is changeable between a maximum aperture and a minimum aperture;
a camera body to which said photographing lens is detachably attached, said camera body being provided with a stepping motor for driving said diaphragm device to change between said maximum aperture and said minimum aperture when said photographing lens is attached to said camera body;
a diaphragm control slider provided in said camera body, wherein said diaphragm control slider is driven by said stepping motor between a first control end that corresponds to said maximum aperture of said diaphragm device and a second control end that corresponds to said minimum aperture of said diaphragm device;
a position detector provided in said camera body, wherein said position detector detects the position of said diaphragm control slider;
an input device, into which an initialization-process command signal is input, wherein said initialization-process command signal commands an initialization process to commence in the camera body;
and
a controller which, upon said initialization-process command signal being input to said input device, drives said diaphragm control slider toward said first control end at high-speed in a stepwise manner via said stepping motor, stores in a memory, as a temporary origin, a position detected by said position detector to which the diaphragm control slider has rebounded after reaching said first control end, and after said diaphragm control slider has rebounded, said controller compares a current position of said diaphragm control slider, detected by said position detector, with said temporary origin while activating the stepping motor to move said diaphragm control slider at a low-speed towards said first control end,
wherein, when said current position of said diaphragm control slider, detected by said position detector, is within a predetermined range of said temporary origin, said controller determines said current position as the origin of said diaphragm control slider.

5 more elements

A diaphragm control apparatus of an interchangeable lens camera, comprising:

a photographing lens provided with an adjustable diaphragm device, in which an aperture lead screw is changeable between a maximum aperture and a minimum aperture;
a camera body to which said photographing lens is detachably attached, said camera body being provided with a drive motor for driving said diaphragm device to change said aperture between said maximum aperture and said minimum aperture when said photographing lens is attached to said camera body;
a diaphragm control slider which is provided in said camera body, wherein said diaphragm control slider moves by rotation of said drive motor between a first control end corresponding to said maximum aperture of said diaphragm device and a second control end corresponding to said minimum aperture of said diaphragm device;
a diaphragm-control-slider biasing spring which is provided in said camera body, wherein said diaphragm-control-slider biasing spring biases said diaphragm control slider toward said first control end;
a diaphragm operatively-associated rod, provided in said photographing lens, which opens and shuts said diaphragm device between said maximum aperture and said minimum aperture by being rotated via the operatively associated movement of said diaphragm control slider provided in said camera body;
and
a diaphragm operatively-associated-rod biasing spring, provided in said photographing lens, which biases said diaphragm operatively-associated rod toward said minimum aperture of said diaphragm device;
wherein the biasing force of said diaphragm-control-slider biasing spring that is applied to bias said diaphragm control slider toward said first control end, which corresponds to said maximum aperture of said diaphragm device, is smaller than the biasing force of said diaphragm operatively-associated-rod biasing spring that is applied to bias said diaphragm operatively-associated rod toward said minimum aperture of said diaphragm device, and
wherein, when said photographing lens is attached to said camera body, part of said biasing force of said diaphragm operatively-associated-rod biasing spring is cancelled by said biasing force of said diaphragm-control-slider biasing spring, and said diaphragm device is positioned at an intermediate open position between said maximum aperture and said minimum aperture.

6 more elements

Dependencies are inferred from the claim text.