Photography – Camera detail – Lens mount
Reexamination Certificate
1998-12-04
2002-01-29
Mahoney, Christopher E. (Department: 2851)
Photography
Camera detail
Lens mount
C396S532000
Reexamination Certificate
active
06341902
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a single-lens reflex camera having data-transmission pins (contact members) at positions other than on the lens mount surface thereof; and in particular, to a photographic lens, a camera body and a camera system of a medium-format single-lens reflex camera.
2. Description of the Related Art
In single-lens reflex cameras of the prior art, a contact pin group (a lens pin group) at a position other than the lens mount surface of the photographic lens thereof has been provided (for example at an inside part of the lens mount surface) having a plurality of contact pins in order to identify open aperture data and minimum aperture data. A corresponding contact pin group (body pin group) having a plurality of contact pins which make contact with the lens pin group is provided in the vicinity of a lens mount surface of the camera body. The electric potential (level) at these contact pin groups are checked; subsequently, the open aperture data and the minimum aperture data are input in the camera body.
Recently, there has been requirements for functions that are not provided in photographic lenses or camera bodies of the prior art. However, when a photographic lens or a camera body is to be equipped with additional new functions, there arises a problem of compatibility between pre-existing and new photographic lenses or camera bodies; in particular, the compatibility of the contact members and the communication system which carries out data transmission between the photographic lens and the camera body.
FIGS. 4 and 5
are examples of lens mounts of a photographic lens and a camera body of the prior art. The aperture data setting pin group (a contact pin group) includes a series of lens pins
75
a,
75
b,
75
c,
75
d,
75
j,
75
k
and
751
. The lens pins
75
a
through
75
d
and
75
j
through
75
l
are aligned in a circle, the center of which lies on the optical axis of photographic lens
71
closer to the optical axis than mount ring
72
and bayonet plate
73
(i.e., inside the concentric circles of the mount ring
72
and the bayonet plate
73
) of the photographic lens
71
. The aperture data is transmitted from the lens pins
75
a,
75
b,
75
c,
75
d,
75
j,
75
k
and
75
l
to corresponding body pins
55
a,
55
b,
55
c,
55
d,
55
j,
55
k
and
55
l,
which serve as data-transmission pins, in order to be read by a camera body
51
. The body pins
55
a
through
55
d
and
55
j
through
55
l
are also aligned in a circle, the center of which lies on the optical axis of the camera body
51
, closer to the optical axis than mount ring
52
or bayonet plate
53
(i.e., inside the concentric circles of the mount ring
52
and the bayonet plate
53
) of the camera body
51
. Each of the lens pins
75
a
through
75
d
and
75
j
through
75
l
is fixed on a protection ring
74
made of an insulating material, each protruding from each hole therefor formed in the protection ring
74
. Each of the body pins
55
a
through
55
d
and
55
j
through
55
l
is also fixed on a pin supporting plate
56
made of an insulating material, each protruding from each hole therefor formed in the pin protection plate
56
. A spring force is applied to each of the body pins
55
a
through
55
d
and
55
j
through
55
l
by a spring (not shown), whereby the body pins
55
a
through
55
d
and
55
j
through
55
l
can protrude from the pin supporting plate
56
or sink therein. Furthermore, the mount ring
52
and the bayonet plate
53
of the camera body
51
and the mount ring
72
and bayonet plate
73
of the photographic lens
71
are all formed from metal. Consequently, when the photographic lens
71
is attached to the camera body
51
, each mount ring (
72
and
52
respectively) and each bayonet plate (
73
and
53
respectively) make contact with each other, wherein the electric potential level thereof becomes the same as ground.
However, when the above-mentioned photographic lens is equipped with new functions such as ROM, an AF motor and a controller therefor, or a lens shutter and a controller therefor; sufficient data or command communication relating to such new functions cannot be carried out using pre-existing, former lens pins
75
a
through
75
d
and
75
j
through
75
l
and body pins
55
a
through
55
d
and
55
j
through
55
l.
Furthermore, though a new-designed photographic lens having additional lens pins can be matched with a new-designed camera body also having additional body pins, if such a new (designed) photographic lens having additional lens pins is attached to a pre-existing camera body, the additional lens pins cannot make contact with any member of the pre-existing camera body. Therefore it is impossible to carry out data or command communication between the new photographic lens and the pre-existing camera body. In other words, the pre-existing camera body cannot recognize the new commands of the new photographic lens.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a photographic lens, a camera body and a camera system having additional new functions, which are compatible with a pre-existing photographic lens, camera body and camera system.
To achieve the object mentioned above, according to the present invention, there is provided a camera body which includes: a plurality of body contact-members which can be in contact with, and electrically connected to, a plurality of lens contact-members of a photographic lens when the photographic lens is attached to the camera body; a communication device which can carry out a first communication for receiving fixed information and also a second communication for transmitting arbitrary information, wherein the first communication is carried out via a predetermined body contact-member group-A chosen from the plurality of body contact-members when a photographic lens which allows the first communication is attached; and wherein the second communication is carried out via a predetermined body contact-member group-B, the body contact-member group-B including the predetermined body contact-member group-A chosen from the plurality of body contact-members when a photographic lens allowing the second communication is attached to the camera body; and an identifying device which determines whether or not an attached photographic lens allows the second communication, via predetermined first and second body contact-members selected from the plurality of body contact-members not belonging to the predetermined body contact-member group-A. The communication device communicates with the attached photographic lens via the second communication when the identifying device identifies the attached photographic lens to be a photographic lens which allows the second communication, and via the first communication when the identifying device identifies that the attached photographic lens is a photographic lens allowing the first communication. The predetermined first and second body contact-members become insulated from each other when the photographic lens allowing the second communication is not attached to the camera body; and wherein the predetermined first and second body contact-members become electrically connected to each other via corresponding lens contact-members of the attached photographic lens. The corresponding lens contact members are in contact with the predetermined first and second body contact-members of the camera body, respectively, when the photographic lens which allows the second communication is attached.
Preferably, the identifying device determines whether or not the attached photographic lens allows the second communication by comparing the electric potential of one of the predetermined first and second body contact-members with the electric potential of the other of the predetermined first and second body contact-members.
Preferably, the camera body supplies electric power to the attached photographic lens via one of the predetermined first and second body contact-members when the identifying d
Horita Satoru
Iikawa Makoto
Kobayashi Tomoaki
Sato Osamu
Suzuki Hiroaki
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Mahoney Christopher E.
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