IMPROVEMENTSINANDRELATINGTOCAMERAS
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 a non-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 of focusing on any subject in a frame a user may wish. This is of particular advantage when a picture is required wherein a non-central subject is to bo in focus.
When one of the focusing devices is in focus, the other focusing device(s) will be out of focus.
Suitably, a switching mechanism is provided for selecting one of the focusing devices, the mechanism having a number of positions cor esponding to the number 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.
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To obtain focusing, the distance of the particular camera subject from the camera itself, is preferably measured by an infra-red beam being directed at the ■ subject, whereafter the beam bounces off the subject back to the camera, and the time taken for the beam to travel is measured to give an indication of the distance the subject is from the camera.
The focusing devices are advantageously designed to focus alternatively close range subjects, medium range subjects, and long range subjects.
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 2 shows 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 self focusing 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 of the' camera, the focusing device 16 being positioned at the centre of the camera, and the focusing device 18 being poisitioned on the left hand side of the
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camera .
A switching mechanism in the form of a toggle switch 20 is also provided for selecting one of the focusing devices to be in focus at any one time, the switch 20 having three positions I, II and III 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 III of th'e switch 20 is situated on the same side of the camera as ts corresponding 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 2 ^, while focusing device 16 when selected (position II on switch 20) is used to focus on a central subject (for example 24), and finally focusing device 18 when selected (position III on switch 20) is used to focus on a left hand side subject (for example 26 ) . The user of the camera 10 thus has the option to take a picture focused on any one of the three subjects 22, 24 and 26, by simply selecting switching mechanism 20
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to either position I if focusing 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 if focusing device 18 is to be used to place subject 26 in focus. At any one time, only one of the focusing device 14, 16 and 18 will be in focus, while the other two 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 off the subject back, to the camera, and the time taken for the 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 infra-red beam bounced back off the subject. The receiving devices are positioned one (see'30) on the right hand side of the camera, one (see 34) on the left, hand side of the camera, and one (see 32.)' 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 comprise two devices one slightly to the right and one slightly to the left of the camera, or three devices one to the right, one to the left and one at the centre of the camera. Focus window means 36 are provided in the lens
12 either in the form of a. coloured frame or a light indicator", in order to indicate" to the user of the camera 10 what subject is in focus at any one time. In particular, the window means 36 is movable across the lens 12 in order to indicate whether either a central subject, right hand side subject, or left hand side subject is in focus. Suitably, the window means 36 is automatically moved in response to the selection of the switch 20, and in particular the window means is moved to the right (see arrow 38) of the lens 12 when position I of the switch 20 is selected, moved to the left (see arrow 40) of the lens 12 when position III of the switch 20 is. selected, and moved to the centre of the lens 12 when position II of the switch 20 is selected. After a picture has been taken, the window means 36 may either have to be manually moved to its next selected position.
or alternatively automatically returned to its centre position.
The camera 10 is preferably a compact camera having a fixed permanent lens 12.