GB2185118A

GB2185118A - Automatic focusing

Info

Publication number: GB2185118A
Application number: GB08530919A
Authority: GB
Inventors: Van Schoonheten Baron Bentinck
Original assignee: JOLLY GOOD PRODUCTION Co
Current assignee: JOLLY GOOD PRODUCTION Co
Priority date: 1985-12-16
Filing date: 1985-12-16
Publication date: 1987-07-08
Also published as: WO1987003705A1; AU6591886A; EP0250463A1; GB8530919D0; JPS63502140A

Abstract

A camera has two or more alternative focusing devices. As shown, one of three focusing devices (14, 16 and 18) is selected by positioning a toggle switch (20) in one of three respective positions I, II and III, switch (20) being biased to position II. A single IR beam is emitted at aperture (28) and a bounced beam is received (a) at apertures (30) and (32) from distant subject (22) using device (14, (b) at apertures (30) and (34) from near subject (24) using device (16) and (c) at apertures (32) and (34) from intermediate subject (26) using device (18). Two or three emitted beams may be employed instead of a single emitted beam.

Description

SPECIFICATION Improvements in and relating to cameras This invention relates to a camera, and in particular to the focusing of a camera.

Prior art automatic focusing cameras focus on the central subject of a picture being taken. Some of these cameras also provide means whereby anon- central subject can be placed in focus if the user so wishes. These means are however, complicated in design and construction, and are relatively difficult and fiddling to use.

In accordance with the present invention, a camera has at least two, preferably three, focusing devices.

Such an arrangement is simple in design and construction, and is very easy to use. In particular, the arrangement provides a quick method offocusing on any subject in a frame a user may wish. This is of particularadvantagewhen a picture is required wherein a non-central subject is in focus.

When one of the focusing devices is in focus, the other focusing device(s) will be out offocus.

Suitably, a switching mechanism is provided for selecting one of the focusing devices, the mechanism having a number of positions corresponding to the num ber of focusing devices.

Preferably, the switching mechanism is a toggle switch which is spring mounted so as to return to a central position when released by a user.

To obtain focusing, the distance ofthe particular camera subjectfromthe camera itself, is preferably measured byan infra-red beam being directed atthe subject, whereafter the beam bounces off the subject backto the camera, andthetimetaken forthe beam to travel is measured to give an indication of the dis tance the subject is from the camera.

Thefocusing devices are advantageously designed to focus alternatively close range subjects, medium range subjects, and long rangesubjects.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a front view of a camera in accordance with the invention, and Figure 2shows a schematic diagram showing the camera of Figure 1.

In Figure 1, a camera 10 is shown having a body portion 11 and a lens 12. The camera 10 also has three seiffocusing devices 14, 16 and 18, which are arranged horizontally in a row across the top of the body portion 11, the focusing device 14 being positioned on the right hand side ofthe camera,the focusing device 16 being positioned atthe centre of the camera, and the focusing device 18 being positioned on the left hand side of the camera.

Aswitching mechanism in the form oaf toggle switch 20 is also provided for selecting one ofthe focusing devices to be in focus at any one time, the switch 20 having three positions l, ll and Ill at which the focusing devices 14, 16 and 18 respectively are alternatively selected.

For simplicity, position II of the switch 20 is centrally situated, while position I of the switch 20 is on the same side of the camera as its corresponding focusing device 14, while position Ill of the switch 20 is situated on the same side of the camera as its cor responding focusing device 18. In consequence, to focus a subject for example on the left, the switch 20 simply needs to be selected towards the left by a user.

The focusing device 14 when selected (position I on switch 20) is used to focus on a right hand side subject (for example 26), while focusing device 16 when selected (position lIon switch 20) is used to focus on a central subject (for example 24), and finally focusing device 18when selected (position Ill on switch 20) is used to focus on a left hand side subject (for example 22).

The user of the camera 10 thus has the option to take a picture focused on any one ofthe three subjects 22,24 and 26, by simply selecting switching mechanism 20to either position I iffocusing device 14 is to be used to place subject 22 in focus, position II if focusing device 16 is to be used to place subject 24 in focus, or position III iffocusing device 18 isto be used to place subject 26 in focus. At any one time, only one ofthefocusing device 14,16 and 18will be in focus, while the othertwo of the focusing devices will be out of focus.

The correct focusing is obtained by measuring the distance of the particular camera subject 22,24 or 26 from the camera 10, by directing an infra-red beam at the subject, whereafter the beam bounces offthe subject back to the camera, and the time taken forthe beam to travel is measured to give an indication of the distance the subject is from the camera. In particular, a single beam directing means 28 is provided at the centre of the camera to direct an infra-red beam at a subject, while three beam receiving devices 30,32 and 34 are provided to receive the infrared beam bounced back off the subject. The receiving devices are positioned one (see 30) on the right hand side of the camera, one (see 32) on the left hand side ofthe camera, and one (see 34) at the centre of the camera.When focusing device 14 is selected to focus a subject on the right, the right and centre receiving devices 30 and 32 are used, and when focusing device 16 is selected to focus a subject in the centre, the right and left receiving devices 30 and 34 are used, and when focusing device 18 is selected to focus a subject on the left, the left and centre receiving devices 32 and 34 are used.

The beam directing means can alternatively com prise two devices one slightlyto the right and one slightly to the left of the camera, orthree devices one to the right, one to the left and one at the centre ofthe camera.

1. A camera having at least two focusing devices.

2. A camera as claimed in Claim 1 having three focusing devices.

3. Acamera as claimed in either Claim 1 or2 including a switching mechanism for alternatively selecting the focusing devices.

4. A camera as claimed in Claim 3 wherein the switching mechanism is a toggle switch biased tow

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in and relating to cameras This invention relates to a camera, and in particular to the focusing of a camera. Prior art automatic focusing cameras focus on the central subject of a picture being taken. Some of these cameras also provide means whereby anon- central subject can be placed in focus if the user so wishes. These means are however, complicated in design and construction, and are relatively difficult and fiddling to use. In accordance with the present invention, a camera has at least two, preferably three, focusing devices. Such an arrangement is simple in design and construction, and is very easy to use. In particular, the arrangement provides a quick method offocusing on any subject in a frame a user may wish. This is of particularadvantagewhen a picture is required wherein a non-central subject is in focus. When one of the focusing devices is in focus, the other focusing device(s) will be out offocus. Suitably, a switching mechanism is provided for selecting one of the focusing devices, the mechanism having a number of positions corresponding to the num ber of focusing devices. Preferably, the switching mechanism is a toggle switch which is spring mounted so as to return to a central position when released by a user. To obtain focusing, the distance ofthe particular camera subjectfromthe camera itself, is preferably measured byan infra-red beam being directed atthe subject, whereafter the beam bounces off the subject backto the camera, andthetimetaken forthe beam to travel is measured to give an indication of the dis tance the subject is from the camera. Thefocusing devices are advantageously designed to focus alternatively close range subjects, medium range subjects, and long rangesubjects. The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a front view of a camera in accordance with the invention, and Figure 2shows a schematic diagram showing the camera of Figure 1. In Figure 1, a camera 10 is shown having a body portion 11 and a lens 12. The camera 10 also has three seiffocusing devices 14, 16 and 18, which are arranged horizontally in a row across the top of the body portion 11, the focusing device 14 being positioned on the right hand side ofthe camera,the focusing device 16 being positioned atthe centre of the camera, and the focusing device 18 being positioned on the left hand side of the camera. Aswitching mechanism in the form oaf toggle switch 20 is also provided for selecting one ofthe focusing devices to be in focus at any one time, the switch 20 having three positions l, ll and Ill at which the focusing devices 14, 16 and 18 respectively are alternatively selected. For simplicity, position II of the switch 20 is centrally situated, while position I of the switch 20 is on the same side of the camera as its corresponding focusing device 14, while position Ill of the switch 20 is situated on the same side of the camera as its cor responding focusing device 18. In consequence, to focus a subject for example on the left, the switch 20 simply needs to be selected towards the left by a user. The focusing device 14 when selected (position I on switch 20) is used to focus on a right hand side subject (for example 26), while focusing device 16 when selected (position lIon switch 20) is used to focus on a central subject (for example 24), and finally focusing device 18when selected (position Ill on switch 20) is used to focus on a left hand side subject (for example 22). The user of the camera 10 thus has the option to take a picture focused on any one ofthe three subjects 22,24 and 26, by simply selecting switching mechanism 20to either position I iffocusing device 14 is to be used to place subject 22 in focus, position II if focusing device 16 is to be used to place subject 24 in focus, or position III iffocusing device 18 isto be used to place subject 26 in focus. At any one time, only one ofthefocusing device 14,16 and 18will be in focus, while the othertwo of the focusing devices will be out of focus. The correct focusing is obtained by measuring the distance of the particular camera subject 22,24 or 26 from the camera 10, by directing an infra-red beam at the subject, whereafter the beam bounces offthe subject back to the camera, and the time taken forthe beam to travel is measured to give an indication of the distance the subject is from the camera. In particular, a single beam directing means 28 is provided at the centre of the camera to direct an infra-red beam at a subject, while three beam receiving devices 30,32 and 34 are provided to receive the infrared beam bounced back off the subject. The receiving devices are positioned one (see 30) on the right hand side of the camera, one (see 32) on the left hand side ofthe camera, and one (see 34) at the centre of the camera.When focusing device 14 is selected to focus a subject on the right, the right and centre receiving devices 30 and 32 are used, and when focusing device 16 is selected to focus a subject in the centre, the right and left receiving devices 30 and 34 are used, and when focusing device 18 is selected to focus a subject on the left, the left and centre receiving devices 32 and 34 are used. The beam directing means can alternatively com prise two devices one slightlyto the right and one slightly to the left of the camera, orthree devices one to the right, one to the left and one at the centre ofthe camera. CLAIMS

1. A camera having at least two focusing devices.

2. A camera as claimed in Claim 1 having three focusing devices.

4. A camera as claimed in Claim 3 wherein the switching mechanism is a toggle switch biased tow ards a central position.

5. Acamera as claimed in either Claim 3 or4 wherein the switching mechanism has a number of positions corresponding to the number of focusing devices.

6. A camera as claimed in any preceding Claim including means to measure the distance of a camera subject from the camera.

7. A camera as claimed in Claim 6 wherein the means comprises devices for directing and receiving an infra-red beam.

8. Acamera as claimed in Claim 7 which includes a beam receiving device for each focusing device.

9. A camera as claimed in Claim 7 or 8 which includes at least one beam directing device.

10. A camera as claimed in any preceding Claim wherein the focusing devices are arranged horizontally in a row across the camera body.

11. A camera substantially as described herein and shown in the accompanying drawings.