JPS6232426A - Camera - Google Patents

Abstract

PURPOSE:To reduce the number of unnecessary terminals by transmitting signals with the same terminal in accordance with a lens of each type though two AF lens different in type are set. CONSTITUTION:Power is supplied to a CPU 12 from the camera side through terminals 14a and 14e, and the CPU 12 outputs data concerning relations between the extent, by which a lens element in the AF lens is moved when couplings 2 and 13 are rotated once, and the extent of movement of an image surface in the camera accompanied with this movement of the lens element to terminals 14b-14d. An old AF lens C is so set that the extent of movement of the image surface accompanied with the movement of th4 lens element and the extent of rotation of a motor have prescribed relations with respect to any interchangeable lens. In the old AF lens, a terminal 17d is connected to the ground through a resistance 21 in case of any lens, and the terminal outputs the low level when the lens is set (before a motor 15 is driven).

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a camera to which an automatic focusing lens barrel (hereinafter referred to as AF lens) can be attached.

(Background of the Invention) Some conventional cameras are equipped with an AF lens and guided to a focused state by signals from the camera. However, a new type of A newly developed for this camera
Attempting to attach an F lens causes inconveniences such as the need to newly provide a terminal compatible with the new AF lens.

(Objective of the Invention) An object of the present invention is to solve these drawbacks and provide a camera to which two different types of AF lenses can be attached and a terminal can be used in common.

(Example) In Figure 1, (A) is a camera, (B) is a newly developed AP lens, (C) is a conventional AP lens, (
D) shows a conventional lens barrel that is not an AF lens.

The camera (A) shown in Figure 1 has a terminal 1a for power supply and a terminal 1 for signal transmission on the mount surface on which the lens barrel is attached.
b to ld, and a ground terminal 1e. The coupling 2 is rotated by a motor 7 inside the camera, which will be described later, and is provided so as to be able to protrude from the mounting surface of the camera. The switching circuit 3 switches the output voltage to the terminal 1a and the signals transmitted to the signal transmission terminals 1b to Id. The motor drive signal generation circuit 4 is a circuit that generates a motor drive signal for a conventional AF lens. The light-receiving element 5 is a focus-adjusting light-receiving element that receives transmitted light from an attached lens. C.P.
For U6, the lens attached to the camera (A) is the new AF lens CB), the old AF lens (C), or a non-AF lens (D).
), receives a signal from the light receiving element 5 to identify the focusing state of the lens, and outputs a driving signal to the motor 7.15. The rotary plate 8 rotates together with the motor 7, and has a transparent part 8a and a light shielding part 8b. Light emitted from the light emitting element 9 reaches the light receiving element 10 via the rotary plate 8. The new AF lens (B) has a CPU 12, a coupling 13 that engages with the coupling 2, and terminals 14a to 14e connected to the terminals 1a to 1e, respectively. These are provided on the lens side mounting surface. The CPU 12 is supplied with power from the camera side via terminals 14a and 14e, and the CPU 12 calculates the amount by which the lens element within the AF lens moves when the coupling 2.13 rotates once, and the amount within the camera due to the movement of this lens element. Data regarding the relationship between the image plane and the amount of movement of the image plane (data unique to the interchangeable lens) are output to terminals 14b to 14d. Here, the terminal 14d is in an open state when the lens is attached (before signals are exchanged between the CPU 6 and the CPTJ 12). Old AF
The lens (C) includes a motor 15, a motor drive circuit 16,
Terminals 17a to 17 connected to terminals 1a to 1e, respectively
It has e. The terminals 17a to 17e are provided on the lens side mount surface. The motor drive circuit 16 is supplied with power from the camera side via terminals 17a and 17e,
receiving motor drive signals via terminals 17b to 17d;
The motor 15 is controlled. In this lens, a motor 15 drives the lens elements within this lens. The rotating plate 18 includes a zero rotating plate 18 rotating together with the motor 15 and an element 19.20.
has the same configuration as 8.9.10 on the camera side. However, the old AF lens (C) is not compatible with any interchangeable lens.
The amount of movement of the image plane due to the movement of the lens element and the motor 15
The rotation amount is set to have a predetermined relationship. Further, in the old AF lens, the terminal 17d is connected to the ground via the resistor 21 in any lens, and outputs a low level when the lens is attached (before the motor 15 is driven). A conventional lens (D) that is not for AF does not have a terminal for connection to the terminals 1a to 1e on the camera side. The lens element is then moved by a manual operation ring (distance ring) not shown.

Next, the lens identification operation and subsequent operations will be explained using the flowchart shown in FIG.

(i) When a new AF lens is attached: When the lens (B) is attached, the signal (open) of the terminal 14d is sent to the port P of CPtJ6 via the terminal 1d. It is input to I. Then, in step (2), the CPU 6 determines whether the signal applied to the boat PI,l is at Lo-level. In the case of this lens, the terminal 14d is in an open state, so the determination is No. If the POI is at a low level, it is the old AF lens (C), so if it is determined as No, it is determined that it is another lens. If NO is determined in step (2), the process proceeds to step (2). In this step, CP
U6 connects to terminal 1b via data bus 6a and switching circuit 3.
~1d outputs a signal asking whether communication is possible. In this case, since the lens (B) has a CPUI 2 and can communicate with the CPU 6, the CPU 12 outputs response signals to the terminals 14b to 14d. This signal is transmitted to terminals 1b to 1d,
It is transmitted to the CPU 6 via the circuit 3 and the data bus 6a. In step (2), the CPU 6 determines whether or not there is a response signal from the lens (B). In this case, since there is a response signal from the CPU 12, it is determined as YES. If the determination is NO here, it means that the lens barrel is not an AF lens but a conventional lens barrel. If YES in step (2), it is determined in step (2) that the attached lens is a new AF lens.

Then, the CPU 6 sends a signal to the switching circuit 3 via the line 6b in step (2), and increases the output voltage Vcc of the switching circuit 3 by 5.
command to switch to v. In response to this, the switching circuit 3 switches the output voltage Vcc to 5V and outputs it to the terminal 1a.

After that, data regarding the amount of movement of the lens elements in the AF lens and the amount of image plane movement are sent from the CPU 12 to the terminals 14b to 14d, 1b, which is transferred to another routine not shown.
~1d, is read into the CPU 6 via the circuit 3 and the data bus 6a. This data is then used when performing automatic focus adjustment.

Next, the operation of automatic focus adjustment will be described. Lens (B)
Light from the subject is guided to the light receiving element 5 through the lens element. The light receiving element 5 generates a photoelectric output corresponding to the focus adjustment state of the lens element T.

The CPU 6 receives this photoelectric output and identifies the focus adjustment state. That is, the actual amount of deviation between the film plane and the image plane on which the subject image is formed, the front focus, and the rear focus are identified. Then, the CPU 6 sets the amount of deviation to zero based on the amount of deviation between the film plane and the image plane, as well as the data regarding the amount of lens movement and the amount of image plane movement obtained from the CPU 12 via the terminals 14b to 14d. The number of rotations the coupling 2 must be made to bring the motor into a focused state is calculated, and the number of rotations the motor 7 must be rotated for that purpose. The motor 7 is driven in a rotational direction corresponding to a front bin signal or a rear pin signal from the CPU 6. The rotation of the motor 7 is transmitted to the coupling 2, and then to the lens side via the coupling 13 that engages with the coupling 2. The lens element within the lens is thereby moved in the direction of the optical axis,
The image plane moves in a direction that coincides with the film plane. C.P.
U6 counts the pulses output to the emitter of the light receiving element (phototransistor) 10 as the rotary plate 8 rotates, and calculates the amount of rotation of the motor 7 by the amount of rotation of the motor calculated as described above. Determine whether it has been reached. When it is detected that the amount of rotation has been reached, the motor 7 is stopped. In this way, a focused state is obtained.

(11) When the old AP lens is installed; Lens (C)
is attached, the signal (Low level) at terminal 17 (f) is input to the port P (I+) of the CPU 6 via the terminal 1d. Then, in step The CPU 6 determines whether or not the lens is an old AF lens.
U6 moves to step (2) and sends a signal to the switching circuit 3 via the line 6b, instructing it to switch the output voltage Vcc of the switching circuit 3 to 3 (2). In response to this, the switching circuit 3 switches the output voltage Vcc to 3V and outputs it to the terminal 1a.

In the case of this lens, since it does not have a CPU, terminal 1
The same output as the terminals 14b to 14d, that is, data regarding the lens movement amount and the image plane movement amount are not output from the terminals 7b to 17d.

Next, the automatic focus adjustment operation will be described. This lens (C
), the subject light is guided to the light receiving element 5 via the lens element in the lens (C), and the light receiving element 5 generates a photoelectric output corresponding to the focus adjustment state of the lens element. CPU6
identifies the focusing state from this. The process up to this point is the same as in the case of lens (B). However, in this case, the CPU 6 detects that the old AF lens (C) is attached, so it does not drive the motor 7, rotary plate 8, and element 9.10.
Then, only the front pin and rear pin identification signals are output.
This is transmitted to the motor drive signal generation circuit 4. The motor drive signal generation circuit 4 outputs the signal from the CPU 6 to the motor 15.
is converted into a signal for driving, and this signal is outputted to terminals 1b to 1d via switching circuit 3. That is, switching circuit 3
When receiving a switching signal for the power supply voltage Vcc from the CPU 6, the communication path between the CPUs 6 and 12 is cut off, and the signal from the motor drive signal generating circuit 4 is switched to be output to the terminals 1b to 1d. Motor drive circuit 16 is circuit 4
The motor 15 is rotated in response to a signal from the motor 1.
5, the lens element is moved in the optical axis direction. Then, the image plane moves in a direction that coincides with the film plane. When the rotary plate 8 rotates together with the motor 15, a pulse output is generated at the emitter of the light receiving element (phototransistor) 20, and this output is transmitted via the terminals 17d and ld. CPU6 boat P
, is transmitted to. As described above, since the amount of rotation of the heptad 150 and the amount of movement of the image plane are set in a predetermined relationship, the pulse output and the amount of movement of the image plane also have a similar relationship. Furthermore, when the CPU 6 outputs the front focus and rear focus signals to the motor drive signal generation circuit 4 as described above, it also calculates the actual amount of deviation between the film plane and the image plane on which the subject image is formed. Therefore, the CPU 6 counts the pulses input to the boat Po1, calculates the amount of image plane movement therefrom, and determines whether this amount of image plane movement matches the above-mentioned actual deviation amount.

When it is determined that the two match, it outputs a signal to the motor drive signal generation circuit 4 to stop the motor 15.

In this way, the motor 15 is stopped and a focused state is obtained.

(iii) When a conventional lens other than an AF lens is attached When the lens (D) is attached, the CPU 6 tries to read the output of the lens side terminal via the terminal 1d. However, since the lens (D) does not have a terminal, the terminal 1d is in an open state as in the case of the lens CB). Therefore, when the CPtJ6 determines whether the signal of the port Po is at the LO-level in step (2), the determination is NO. Then, the process proceeds to step (2), and a signal inquiring whether communication is possible is outputted via the terminals 1b to 1d. In this case the lens (
D) does not have CPU6, so it is
No response signal is returned from D). Therefore, the CPU 6 determines in step ■ that there is no response signal, outputs a determination output of No, and then in step ■, the attached lens is A.
It is determined that the lens is a conventional lens that is not an F lens. Thereafter, the CPU 6 proceeds to step (2), sends a signal to the switching circuit 3 via the line 6b, and outputs the output voltage VC of the switching circuit 3.
Issue a command to set C to zero. The switching circuit 3 then sets the output voltage Vcc to zero. In other words, turn off the power.

Subsequent focus adjustment is performed by manually operating a manual operation ring provided on the lens (D). Of course, the output from step ■ or ■ causes CPU 6 to cp
Signals for communicating with υ12, signals for driving motor 15, etc. are no longer output. The switching circuit 3 also enters a state in which all signals transmitted to the terminals 1a to 1e are cut off by a similar output.

In this embodiment, the coupling 2 protrudes from the mounting surface of the camera only when it is determined that the new AF lens (B) is attached to the camera (A).

Also, in the embodiment, it was stated that when the old AF lens (C) is attached, the motor drive signal is output from the terminals 1b to 1d.
As is clear from the description of the embodiment, in detail, the terminal 1b,
A motor drive signal is output from the IC, and a pulse output from the lens is input from the terminal 1d.

(Effects of the Invention) As detailed above, according to the present invention, even if two different types of AF lenses are attached, signals corresponding to each type of lens can be transmitted through the same terminal.

Therefore, the number of terminals is not increased unnecessarily and the effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.
A) is the camera, (B) is the new AF lens, (C) is the old AF
Lens, (D) is a conventional lens that is not an AF lens, 2nd
The figure is a flowchart for identifying the type of lens. [Explanation of symbols of main parts] 1a to 1e---one terminal

Claims (1)

[Claims] When a first type of AF lens is attached, a second type of AF lens can be attached to the camera which emits an output corresponding to the first type of AF lens from the terminal, and the second type of AF lens is attached to the camera. A camera characterized in that when it is detected that an AF lens is attached, an output corresponding to the second type of AF lens is output from the terminal.