JPS58125005A - Zoom lens - Google Patents

Abstract

PURPOSE:To use a motor-driven means to set a focusing means to a prescribed position quickly and smoothly, by driving either of a focus part driving means and a zoom part driving means at least by the indication from the external. CONSTITUTION:Flow sheet of the focusing function and the zooming function are shown in the left and the right in figure. In explanation of the focusing function, the current position of a focusing means FM having a focusing lens is detected in a detecting means FDM by a position sensor and is recorded. A target object distance set by the operation from the external is stored in a storage means M1 by an object distance setting means ODM where this target object distance is set preliminarily.A signal OS2 of the object distance which is set preliminarily by the operation from the external and a signal OS1 of the current object distance are inputted to a comparing means OCM, and a driving quantity of a focusing driving means FMM such as a focus motor is determined on a basis of the operation in an operating means SM, and the focusing means FM is driven to the set object distance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zoom lens, and more particularly to a zoom lens having a preset focus function and a preset zooming function that also perform the power focusing function and the power zooming function.

Conventionally, in zoom lenses that have power focusing and power zooming functions, these functions have been performed by independent control mechanisms. Further, these operations were performed by the photographer while observing a monitor or the like. For this reason, it is not quick enough to set a fixed focus position or a zoom position of RJT.

SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens that eliminates the drawbacks of the prior art described above and can quickly and smoothly set a predetermined focus position and zoom position using motorized means.

For example, in presetting the focus position, the current position of the lens helicoid having the focusing lens is detected by a position sensor and recorded by a recording circuit. The purpose is to compare and calculate the desired subject distance input later and then move the focusing lens directly to a predetermined distance using a drive motor or the like. The zoom position setting is also similar to the focus position setting described above.

Next, the functions of the zoom lens that performs the preset focus function and the Grisef1 zoom function of the present invention will be explained using the block diagram shown in FIG.

FIG. 1 shows the flow of a block diagram of the focusing function and zooming function in the zoom lens of the present invention. The left side shows the flow of the focusing function and the right side shows the flow of the zooming function. The focusing function of the block diagram will be explained.

The current position of the focusing means FM, such as a helicoid having a focusing lens, is detected by the focus part position detecting means FDM.

Then, the current subject distance signal is recorded.

On the other hand, a signal is stored in the memory hand 6*1 by subject distance setting means Of) for presetting a desired subject distance by operating a button or the like from the outside.

Then, a signal O82 of the subject distance previously set by an external switch operation, etc. and a signal O81 of the current subject distance.
is input to the comparison means OCM.

Then, the comparison means OCM compares the current object distance signal and the set object distance signal.
By calculating, the drive of the focusing drive means FMM such as a focus motor is determined, and the focusing means FM is driven to the set object distance. This completes one cycle.

Next time as well, the current position of the focusing means is similarly detected by the focusing section position detecting means FDM and recorded as a subject distance signal.

The operating principle of the zooming function shown in the block diagram on the right side of FIG. 1 is the same as that of the focusing function.

That is, the zooming position which is the current focal length is detected by the zooming unit position detection means Zf)M, and the comparison means FCM compares the focal length signal FS2 with the focal length signal FS2 which is the zoom position from the recording means M2 set in advance. The calculation means SM calculates 0, drives the zooming means ZM, and sets the zooming lens to a preset 1- zoom position.

The number of subject distances and focal lengths to be focused in advance in the zoom lens according to the present invention may be 4i numbers, and
Of course, it is also possible to arbitrarily change the number to IN.

By setting the combination of subject distance and focal length in advance, you can quickly achieve a combination suitable for various scenes, and by pressing the preset button depending on the scene, you can You can easily capture the scene you envision.

Furthermore, if the function of the present invention is applied to a zoom lens with an autofocus function, only the focal length can be determined in advance, and -C
It also has a timer that allows you to quickly take pictures according to your desired purpose just by setting it on, and you can easily operate the focusing and zooming functions in chronological order.

As described above, according to the zoom lens according to the present invention, if the subject distance and focal length are set in advance, the desired shooting can be quickly performed at the zoom position of the predetermined subject distance and focal length with a simple operation from the outside. And you can shoot smoothly.

[Brief explanation of drawings]

FIG. 1 is a block diagram for continuously operating the focusing function and zooming function in a zoom lens according to the present invention. % Applicant: Canon Co., Ltd. (7"゛°゛-・Agent: Gi Marushima
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Claims (4)

[Claims] (1) A focus unit driving means for moving a focusing lens to a preset focus position, and a zoom unit driving unit for moving the entire zoom lens to a preset zoom position, and the focus unit is driven by an external instruction. A zoom lens characterized in that at least one of the means and the zoom unit driving means is driven. (2) The driving amount of the focusing lens by the focusing unit driving means is determined by detecting the position of the focusing lens with a position detection sensor, comparing it with a preset focus position, and then determining the amount of driving of the focusing lens. A zoom lens according to claim 1. (3) A patent characterized in that the drive amount of the zoom lens by the zoom unit driving means is determined after the position of the zoom unit is detected by a position sensor and compared with a preset zoom position. A zoom lens according to claim 1. (4) The zoom lens according to claim 1, characterized in that the predetermined focus positions are black. <5)) The zoom lens according to claim 1, characterized in that a plurality of preset zoom positions are provided.