Photography – Camera detail – Lens mount
Reexamination Certificate
1998-12-04
2002-01-08
Mahoney, Christopher E. (Department: 2851)
Photography
Camera detail
Lens mount
Reexamination Certificate
active
06336754
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
75
l.
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.
Further, if the photographic lens incorporates a control device such as a CPU, or if the photographic lens does not incorporate the control device such as a CPU but incorporates a lens data memory such as a ROM, it is necessary to firstly identify whether the attached photographic lens is a ROM-incorporated lens or a CPU-incorporated lens. However, as compared with the data loading time from the ROM, the CPU requires a longer start-up time before executing the program after the power is turned ON. Thus, a longer time is required to identify the type of photographic lens attached to the camera body.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a photographic lens, a camera body and a camera system, each of which can immediately identify whether the photographic lens attached to the camera body incorporates a memory or a control device.
To achieve the object mentioned above, according to the present invention, there is provided a camera body in which, when a photographic lens is attached to the camera body, data exchange is carried out by communicating with the photographic lens via a plurality of contact pins electrically connected to each other. The camera body includes: a reset pin as one of the contact pins which outputs a reset signal and a reset release signal; and an identifying pin as another of the contact pins for identifying an attached photographic lens.
Preferably, an identifying device is provided which identifies an attached photographic lens according to the change of electric potential of the identifying pin upon the output of the reset release signal to the reset pin.
Preferably, whether or not the electric potential of the identifying pin changes is detected immediately after the output of the reset release signal to the reset pin; and when a change of electric potential is detected, the identifying device identifies that an attached photographic lens incorporates a memory.
Preferably, the reset signal is firstly output to the reset pin, then whether or not the electric potential of the identifying pin changes is detected by the output of the reset release signal to the reset pin; and when a change of electric potential level is detected, the identifying device identifies that an attached photographic lens incorporates a control device.
According to another aspect of the present invention, there is provided a photographic lens including a plurality of contact pins including a reset pin and an identifying pin; wherein data communication is carried out via contact of the contact pins when the photographic lens is attached to a camera body, the photographic lens includes: a memory not including a control device; and a response device in which, when the reset pin receives a reset release signal from the camera body, the electric potential of the identifying pin changes.
Preferably, when the reset release signal is applied to the reset pin, the response device is synchronized with a clock input from the camera body via a data pin other than the reset pin or the identifying pin, wherein data recorded in the memory is
Horita Satoru
Kobayashi Takahiro
Kobayashi Tomoaki
Sato Osamu
Tatamiya Hisashi
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Mahoney Christopher E.
LandOfFree
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