Method of and apparatus for establishing a programmable exposure response of camera
AssigneeOlympus Optical Co., Ltd.
InventorTetsuo Miyasaka
Life of this patent
Estimating the term…
Abstract
When establishing a program exposure response of a camera, an EV value is calculated from the brightness of an object being photographed, a film speed and the like, and a programmed calculation is made on the basis of a preset program response and the EV value to determine an exposure period and a diaphragm aperture in the absence of a program shift input. However, in the presence of a program shift operation, the relationship between an exposure period and a diaphragm aperture is shifted through a given number of steps, and a new program response is established so that the exposure period and the diaphragm aperture varies according to an EV value from their shifted value, thus determining an exposure control value.
Claims17
A method of establishing a program exposure response of a camera having a shift operating member for shifting from a point along a preset program response contained in a memory to another point along another program response, the shift value also being stored in memory, comprising the steps of:
- determining a point, representing at least one exposure controlling value, on a first preset program response comprising a combination of an exposure period and a diaphragm aperture which is determined by an EV value as a function of the brightness of an object being photographed and a film speed and being represented in terms of a constant which depends on the relationship between the exposure period and the diaphragm aperture;
- shifting the combination of the exposure period and the diaphragm aperture through a given number of steps in a direction to maintain an equivalent EV value as the exposure control value at said point responsive to the operation of the shift operation member through a like member of steps;
- setting a second program response including the exposure control value comprising a combination of the exposure period and the diaphragm aperture which are obtained subsequent to the shift operation and separated from the first program response;
- and determining a combination of subsequent exposure period and diaphragm aperture values along the second program response in accordance with an EV value.
An apparatus for establishing a program exposure response of a camera, comprising:
- a shift operating member;
- first calculation means for calculating an EV value from the brightness of an object being photographed and a film speed;
- first memory means for storing a constant of a program response which is used to determine a combination of an exposure period and a diaphragm aperture corresponding to an EV value;
- second calculation means for calculating an exposure period and a diaphragm aperture on the basis of outputs from the first calculation means and the first memory means as a function of an exposure interlocked extent for the exposure period and the diaphragm aperture;
- third calculation means for shifting an exposure period and a diaphragm aperture which are output from the second calculation means through a given number of steps in opposite directions in response to an operation of said shift operating member;
- and fourth calculation means for calculating a constant of a program response which includes an exposure period and a diaphragm aperture which are output from the third calculation means and which is used to determine a combination of an exposure period and a diaphragm aperture corresponding to an EV value, and for causing the calculated constant to be stored in the first memory means in response to an operation of the shift operating member.
A method for establishing a program exposure response for a camera having:
- photometry means for determining the brightness of an image to be photographed;
- memory means for storing a preset program representing the relationship between diaphragm aperture and exposure period values, which values vary in accordance with the preset program response dependent upon changes in the EV value, and a shift initiating member, said method comprising the steps of:
- determining EV value as a function of the brightness value developed by the photometry circuit;
- determining the diaphragm value and exposure period as a function of the EV value and the preset program value;
- shifting the values of the diaphragm aperture and exposure period respectively in opposing direction for each operation of said shift member;
- establishing a new program response as a function of the diaphragm aperture and exposure period established responsive to a shift operation;
- and
- determining the program response according to the shifted exposure period diaphragm aperture values.
A method of establishing a program exposure response of a cameraa having a shift operating member for shifting from a point along an existing program response contained in a memory to another point along another program response contained in the memory, the shift value and maximum and minimum lens diaphragm aperture values and film speed also being stored in the memory, comprising the steps of:
- (a) obtaining and storing a brightness value of the image being photographed;
- (b) determining the EV value based on the brightness value, the maximum aperture value and the film speed value;
- (c) comparing the EV value calculated in step (b) with the minimum and maximum aperture values and shutter speed values stored in memory;
- (d) setting the aperture and shutter speed values at the minimum values if the EV value is less than the lowest diaphragm aperture and shutter speed values;
- (e) setting the aperture and shutter values equal to the maximum aperture and shutter values in the event that the EV value is greater than the maximum diaphragm aperture and shutter speed values;
- (f) calculating the shutter speed value when the EV value lies between the maximum diaphragm aperture and shutter speed values and the minimum aperture and shutter values wherein the shutter speed value TVs=1/2(EV+Px) wherein EV is the EV value calculated in step (b) and Px is the stored program response value stored in memory;
- (g) determining the diaphragm aperture value AVx from the EV value calculated at step (b) and the shutter speed value calculated at step (f);
- (h) setting the diaphragm aperture value at the minimum aperture value if the aperture value calculated at step (g) is less than the minimum diaphragm aperture value stored in memory;
- (i) re-calculating the shutter speed value using the EV value and aperture values obtained at steps (b) and (h) respectively;
- (j) setting the diaphragm aperture value at the highest aperture value stored in memory when the aperture value calculated at step (g) is greater than the highest diaphragm aperture value;
- (k) recalculating the shutter speed value using the diaphragm aperture value established at step (j) and the EV value calculated at step (b);
- (l) setting the shutter speed value at the lowest shutter speed value when the shutter speed value calculated at step (f) is less than the lowest shutter speed value stored in memory;
- (m) calculating the diaphragm aperture value according to the EV value calculated at step (b) and the diaphragm aperture value established at step (k);
- (n) setting the shutter speed value at the high shutter speed value stored in memory in the event that the shutter speed calculated at step (f) is greater than the high shutter speed value stored in memory;
- (o) re-calculating the diaphragm aperture value according to the EV value calculated at step (b) and the diaphragm aperture value determined at step (n).
Dependencies are inferred from the claim text.