US5283607A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic lens control system
Assignee: Pentax Corp
•
Filing: 1992-05-11
•
Granted: 1994-02-01
•
Expires: 2012-05-11
Abstract
Abstract An image magnification control device for a camera. Control focal length required to maintain an image magnification constant is computed based upon defocus information detected by using a light having passed through a photographic lens. In case focal length of the photographic lens comes out of a range wherein the set image magnification can be obtained, various operations such as shutter-release lock operation are executed depending upon designs.
Inventors
- 👤 Noboru Suzuki
- 👤 Shigeo Toji
- 👤 Masahiro Kawasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:34
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/02; G02B7/04; G02B7/10; G02B7/102; G02B7/28; G02B7/282
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
An image magnification control device for a camera comprising: distance detection means for detecting a distance "X 0 " between a rear focal point of a photographic lens and an in-focus position from a delivery-amount of a focusing lens; defocus information detection means for detecting a defocus information "dx" of the photographic lens by using a light having passed through the photographic lens; focal length detection means for detecting a focal length "f 0 " of the photographic lens; image magnification setting means for setting an image magnification "m 0 " for taking a photograph; computation means for computing a control focal length "f 1 " in accordance with an equation: ##EQU6## using said x 0 , d x , f 0 and m 0 ; and focal length control means for changing the focal length of the photographic lens so as to meet said control focal length, said focal length control means comprising motor drive means for driving and varying the focal length of the photographic lens.
Claim 2
Dependent Claim
168 words
An image magnification control device for a camera comprising: distance detection means for detecting a distance "X 0 " between a rear focal point of a photographic lens and an in-focus position from a delivery-amount of a focusing lens; defocus information detection means for detecting a defocus information "dx" of the photographic lens by using a light having passed through the photographic lens; focal length detection means for detecting a focal length "f 0 " of the photographic lens; image magnification setting means for setting an image magnification "m 0 " for taking a photograph; computation means for computing a control focal length "f 1 " in accordance with an equation: ##EQU6## using said x 0 , d x , f 0 and m 0 ; and focal length control means for changing the focal length of the photographic lens so as to meet said control focal length, said focal length control means comprising motor drive means for driving and varying the focal length of the photographic lens.
Claim 3
Dependent Claim
138 words
An image magnification control device for a camera wherein either a single-shot photographing mode or a sequential-shot photographic mode can be selected, said device comprising: image magnification setting means for setting an image magnification to a certain magnification, said image magnification setting means comprising an image magnification input selector that allows a user to select among a plurality of magnifications; and control means for driving a photographic lens so as to maintain the image magnification set by said image magnification setting means, wherein said control means drives said photographic lens, in case the sequential-shot mode is selected, in such a fashion that once a subject is focused at the image magnification set by said image magnification setting means in the sequential-shot photographing mode, a focusing operation is sequentially performed at the set image magnification as a subject moves.
Claim 4
Dependent Claim
138 words
An image magnification control device for a camera wherein either a single-shot photographing mode or a sequential-shot photographic mode can be selected, said device comprising: image magnification setting means for setting an image magnification to a certain magnification, said image magnification setting means comprising an image magnification input selector that allows a user to select among a plurality of magnifications; and control means for driving a photographic lens so as to maintain the image magnification set by said image magnification setting means, wherein said control means drives said photographic lens, in case the sequential-shot mode is selected, in such a fashion that once a subject is focused at the image magnification set by said image magnification setting means in the sequential-shot photographing mode, a focusing operation is sequentially performed at the set image magnification as a subject moves.
Claim 5
Dependent Claim
141 words
An image magnification control device for a camera wherein either a focus-priority mode or a shutter-release-priority mode can be selected, said device comprising: image magnification setting means for setting an image magnification to a certain magnification, said image magnification setting means comprising an image magnification input selector that allows a user to select among a plurality of magnifications; and control means for driving a photographic lens so as to maintain the image magnification set by said image magnification setting means, wherein said control means executes a focus-lock operation when a subject is focused in the focus-priority mode while the image magnification has not been set, and wherein said control means executes image magnification control without executing the focus-lock operation when a subject is focused in the focus-priority mode while the image magnification has been set by said image magnification setting means.
Claim 6
Dependent Claim
141 words
An image magnification control device for a camera wherein either a focus-priority mode or a shutter-release-priority mode can be selected, said device comprising: image magnification setting means for setting an image magnification to a certain magnification, said image magnification setting means comprising an image magnification input selector that allows a user to select among a plurality of magnifications; and control means for driving a photographic lens so as to maintain the image magnification set by said image magnification setting means, wherein said control means executes a focus-lock operation when a subject is focused in the focus-priority mode while the image magnification has not been set, and wherein said control means executes image magnification control without executing the focus-lock operation when a subject is focused in the focus-priority mode while the image magnification has been set by said image magnification setting means.
References Cited (Backward Citations)
JPS53113527A
Cited
JPS5425819A
Cited
US4145732A
Cited
US4156933A
Cited
US4446526A
Cited
JPS58103273A
Cited
US4560267A
Cited
JPS5964816A
Cited
US4508443A
Cited
US4623238A
Cited
US4509842A
Cited
JPS601602A
Cited
JPS6126015A
Cited
JPS6138917A
Cited
US4717933A
Cited
JPS61230111A
Cited
JPS62118328A
Cited
JPS62133431A
Cited
JPS62133430A
Cited
JPS62200340A
Cited
JPS635331A
Cited
US5063402A
Cited
JPS63131112A
Cited
JPS63189817A
Cited
US4935763A
Cited
JPS63220118A
Cited
JPS6444429A
Cited
JPS6444428A
Cited
JPS6456406A
Cited
JPS6462608A
Cited
US5113209A
Cited
US4908643A
Cited
JPS6479713A
Cited
JPH0199012A
Cited
JPH0199011A
Cited
JPH01123206A
Cited
US4951075A
Cited
JPH01179113A
Cited
JPH01232311A
Cited
US4962400A
Cited
JPH01307711A
Cited
JPH01131509A
Cited
JPH0212116A
Cited
US5093680A
Cited
US5159377A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-01-31 | 1997-08-02 | 1998-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-31 | 2001-08-02 | 2002-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-31 | 2005-08-02 | 2006-02-01 | $7700.00 | Window Closed / Lapsed |