Photography – Having wireless remote control circuit
Reexamination Certificate
2002-02-12
2004-06-08
Fuller, Rodney (Department: 2851)
Photography
Having wireless remote control circuit
C396S182000
Reexamination Certificate
active
06748165
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photographing system in which flash photographing is performed in such a manner that a camera and a flash device cooperate with each other, and also relates to a photographic information transmission system in which a first hand-held terminal such as a camera sends a signal relating to photographing to the second hand-held terminal to control a second hand-held terminal such as a flash device.
2. Description of the Related Art
Nowadays, cameras are used in various manners. For example, flash photographing is performed in such a manner that a camera cooperates with an additional device such as a flash device, and photographic data of a camera is sent to a cellular phone. In doing such operations, a photographic information transmission system is used which interconnects a first hand-held terminal such as a camera and a second hand-held terminal such as a flash device.
As an example of such a photographic information transmission system, a photographing system in which a camera and a flash device cooperate with each other to perform flash photographing will be described below.
In this type of photographing system, a common setup is such that a flash device is directly attached to the hot shoe of a camera or that a flash device is connected to the hot shoe of a camera by a cable so that the camera and the flash device are separated from each other by several meters.
In particular, flash photographing with sophisticated lighting is sometimes performed in such a manner that an extension cable is branched so as to connect a plurality of flash devices to a single camera and the flash devices are caused to flash simultaneously with their quantities of flash set independently. In this type of photographing system, it is necessary to use an extension cable having a lot of branches (and subbranches) to connect a plurality of flash devices to a single camera; cumbersome setup work is necessary.
In view of this, recently, a photographing system has been put into practical use in which flash control is performed wirelessly without using any extension cables between a camera and a plurality of flash devices (wireless communication using a flash pulse train is performed).
FIG. 23
to
FIG. 25
show an example of such a photographing system, which will be described below.
In this photographing system, flash photographing is performed in the following manner. A master flash device
101
provided between a camera
102
and a plurality of flash devices
103
and
104
generates, as a communication means, a flash pulse train consisting of flash pulses having very small quantities of flash, which is sent from the master flash device
101
to the flash devices
103
and
104
.
In this photographing system, preset information is correlated with pulse intervals of a flash pulse train. Information is sent from the camera
102
to the flash devices
103
and
104
being carried by a flash pulse train. In response, the flash devices
103
and
104
emit preliminary flashes and main flashes.
The preliminary flashing and the main flashing will be described below.
(1) Preliminary Flashing
The preliminary flashing will be described with reference to FIG.
24
.
FIG. 24
shows a relationship between flash pulse trains generated by the master flash device and preliminary flashes emitted by the flash devices
103
and
104
. Specifically, FIG.
24
(
a
) shows flash pulse trains generated by the master flash device
101
. FIG.
24
(
b
) shows timing with which the master flash device
101
generates flash pulses. FIG.
24
(
c
) shows timing with which the first flash device
103
emits a preliminary flash. FIG.
24
(
d
) shows timing with which the second flash device
104
emits a preliminary flash.
In this photographing system, the master flash device
101
sends an identifying signal of the camera
102
to the first and second flash devices
103
and
104
prior to photographing.
The first and second flash devices
103
and
104
has recognized an identifying signal of the master flash device
101
in advance so as to function in response to the identifying signal sent from the master flash device
101
.
In sending an identifying signal of the camera
102
itself to the first and second flash devices
103
and
104
, the master flash device
101
selects, as the identifying signal, one of a plurality of channels (i.e., combinations of presence and absence of a flash pulse (for a plurality of expected flash pulses)). The first and second flash devices
103
and
104
have the same selecting function, and the same channel as set in the master flash device
101
is set in the first and second flash devices
103
and
104
.
In FIG.
24
(
a
), symbol P
1
denotes a flash pulse train of a command of an identifying signal generated by the master flash device
101
. An expected cycle t of generation of flash pulses is predetermined. In the pulse train P
1
, four flash pulses are generated at maximum. The first and second flash pulses are always generated for prevention of a malfunction and recognition of a start of communication. Four master flash devices
101
can be recognized by combinations of presence and absence of the third and fourth flash pulses (in FIG.
24
(
a
), a solid-line flash pulse indicates “on” and a broken-line flash pulse indicates “on” or “off”). One of the four combinations is selected and determined as an identifying signal of the camera
102
.
A pulse train P
2
shown in FIG.
24
(
a
) is a flash pulse train to be used for selecting a particular one of a plurality of flash devices (i.e., the first and second flash devices
103
and
104
). An identifying signal corresponding to each flash device is selected because a plurality of flash devices may exist. In the pulse train P
2
four combinations of flash pulses are possible depending on presence and absence of a flash pulse (for two expected flash pulses) and hence can specify four flash devices. An identifying signal of a flash device is specified to determine one flash device from the four.
Synchronization is established at the first flash pulse of a flash pulse train such as the pulse train P
1
or P
2
shown in FIG.
24
. The first flash device
103
, for example, detects presence/absence of a flash pulse in every expected cycle t. When detecting a flash pulse block such as the pulse train P
1
or P
2
shown in
FIG. 24
, the first flash device
103
judges whether the master flash device
101
is selected and whether the first flash device
103
itself is selected.
Then, the master flash device
101
sends a command (i.e., a flash pulse train P
3
shown in
FIG. 24
) for causing only the selected first flash device
103
to emit a flash of a small quantity.
Immediately thereafter, the selected first flash device
103
emits a preliminary flash of a predetermined quantity as shown in FIG.
24
(
c
). The preliminary flash is detected by a light-receiving element of the camera
102
via a photographic lens (not shown).
Each of the first and second flash devices
103
and
104
does not respond any more unless its own identifying signal is newly selected. Therefore, in newly sending a pre-flash command to another flash device, the master flash device
101
needs to send pulse trains P
4
-P
6
as shown in FIG.
24
(
a
). In response to the pulse trains P
4
-P
6
, the second flash device
104
emits a preliminary flash. The pulse trains P
4
-P
6
correspond to the respective pulse trains P
1
-P
3
for the first flash device
103
.
The interval between the pulse trains P
1
-P
6
is set at least two times the duration of each flash pulse.
In this manner, the master flash device
101
sends pre-flash instructions in order to the first and second flash devices
103
and
104
and the first and second flash devices
103
and
104
emit preliminary flashes as shown in FIGS.
24
(
c
) and
24
(
d
).
The camera
102
calculates quantities of flashes to be emitted in main flashing based on quantities of reflected light from an object which is produced by reflecting
Fuller Rodney
Nikon Corporation
Smith Arthur A
LandOfFree
Photographing system and photographic information... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photographing system and photographic information..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photographing system and photographic information... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3362742