Abstract:
This camera includes two kinds of photographing modes, a normal photographing mode and a trimming photographing mode of telephotographing in pseudo. The focal length variator for changing the focal length of a zoom lens is formed by a first cam corresponding to the normal photographing, a second cam corresponding to trimming photographing, and a transition area cam connecting the first cam and the second cam. Thus, at the time of transition from the normal photographing mode to the trimming photographing mode, or the transition from the trimming photographing mode to the normal photographing mode, the focal length of the zoom lens is changed to the focal length corresponding to the photographing mode by zooming operation to facilitate change of the photographing mode and always set a view finder to a suitable angle of view corresponding to the focal length set in the zoom lens.

Description:
This application is based on the patent application No. 11-204252 filed in Japan, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a camera and particularly to the camera capable of producing a trimmed image to be scheduled for printing a part of photographic image in a subsequent printing process. 
     2. Prior Art 
     Generally in a camera using a zoom lens as a photographing lens, the focal length of a finder lens is varied interlocking with the zooming operation to make the angle of view of the photographing lens coincide with the angle of view of the finder. 
     With such a camera, in normal photographing, the range of a field of view confirmed through the finder is photographed, so it is not a special obstacle to photographing. 
     Further, it is known that a trimming photographing camera is capable of obtaining a picture having a pseudo telephotographic effect as if it is photographed by a telephoto lens by trimming the top and bottom and left and right of a photographed image in printing. This camera is adapted to trim the top and bottom and left and right of a photographing image plane in a subsequent printing process according to the trimming information preset in photographing and enlarge the image plane to be printed, thereby obtaining a photo having a pseudo telephotographic effect. Such a photographing mode of being scheduled for printing a part of a photographed image plane in printing will be called trimming photographing mode herein after. 
     Furthermore, it is called a substantial focal length when it includes a real focal length in normal mode, and a pseudo focal length in trimming mode. 
     In the case of photographing in the trimming mode with this camera, since the angle of view corresponding to the pseudo focal length does not coincide with the angle of view of the finder, it is necessary that only the angle of view of the finder is changed to make the range of visual field of the finder match the image range of a photo obtained by trimming in subsequent printing process, and the range to be trimming photographed can be confirmed through the viewfinder. 
     Therefore, it has been proposed that in the zoom lens type camera capable of trimming photographing, at the time of trimming photographing, a converter lens is inserted in a finder optical system to change the angle of view of the finder only to the angle of view of pseudo telephotographing (See Japanese Patent Laid-Open No. Hei 4-335332). 
     In addition to this, it has been proposed that the focal length of an objective lens of the finder optical system is changed to change the angle of view of the finder only (See Japanese Patent Laid-Open No. Hei 5-61093). 
     In the known zoom lens type camera capable of trimming photographing, zooming operation is conducted in the normal photographing mode, the focal length of the photographing lens is moved to the telephoto side to be set to the maximum focal length, and then when zooming operation is further conducted, it is switched from the normal photographing mode to the trimming photographing mode, and with the zoom lens still set to the maximum focal length, the trimming magnification is increased, whereby the pseudo focal length is increased so as to obtain a printed image with a larger telephotographic effect than that in the normal photographing mode. 
     In this constitution, it is desired that also in the trimming photographing mode, similarly to the case of photographing in the normal photographing mode, the optimum photographing magnification, that is, the optimum substantial focal length can be set, and it is desirable that in switching from the normal photographing mode to the trimming photographing mode, the substantial focal length is continuously varied to set an arbitrary pseudo focal length. The continuous variation of the pseudo focal length, however, has the disadvantage that since an arbitrary trimming magnification is set in every photographing, setting of trimming magnification in print work becomes complicated. 
     Therefore, in the camera disclosed in Japanese Patent Laid-Open No. Hei 4-335332, the trimming magnification is previously set to plural, and in switching from the normal photographing mode to the trimming photographing mode, the focal length of a zoom lens is changed to the wide angle side so that the real focal length set in the photographing lens before switching becomes substantially equal to the pseudo focal length in the trimming photographing mode after switching. 
     According to such constitution, the angle of view of the finder before and after switching the photographing mode is substantially kept constant, but during switching of the photographing mode, the zooming operation is temporarily stopped, resulting in giving a feeling of physical disorder to a user. 
     Further, in such constitution, it is necessary to provide a space and a special driving mechanism for inserting and separating a converter lens in and from the interior of the finder, which results in the disadvantage that the camera becomes bulky. 
     On the other hand, in the configuration where the focal length of the objective lens in the finder optical system is changed to change only the angle of view of the finder, there is provided a structure of moving the objective lens of the finder optical system by a finder cam driven interlocking with rotation of the zoom ring of the photographing lens to change the focal length of the objective lens. 
     The finder cam is provided with two sets of cam grooves, a cam groove used in the case of photographing in the normal mode and a cam groove used in the case of photographing in the trimming photographing mode, whereby in the case of switching from the normal mode to the trimming photographing mode or switching inversely, that is, switching the photographing mode, one of the cam grooves suitable to the photographing mode is selected to move the objective lens of the finder optical system. 
     However, switching to one of the cam grooves suitable to the photographing mode can not be performed in the middle position of the maximum and minimum focal length of the objective lens of the finder optical system structurally, but switching between the cam grooves can be performed in the position of the maximum or minimum focal length of the objective lens, that is, only at the ends of the cam grooves. 
     Therefore, the disadvantage is that every time the photographing mode is switched, the zoom ring of the photographing lens is operated to set the focal length of the photographing lens to the maximum or minimum value, that is, to set the photographing lens to the limit position on the telephoto side or the wide angle side, and the finder cam interlocking with the zoom ring should be moved to locate an engagement pin for driving the objective lens of the finder optical system at the end of the cam groove. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above circumstances and provides a camera capable of simply switching between two kinds of photographing modes, the normal photographing mode and the trimming photographing mode capable of telephotographing in pseudo by the zooming operation. 
     Further, the invention provides a camera which is capable of switching between two kinds of photographing modes, the normal photographing mode and the trimming photographing mode and includes a view finder in which a suitable angle of view is always set corresponding to the focal length set in a zoom lens by switching the photographing mode. 
     Further, the invention provides a camera including a zoom lens in which plural focal lengths are previously set for the normal photographing area corresponding to the normal photographing mode and the trimming photographing area corresponding to the trimming photographing mode, respectively, and a view finder in which a suitable angle of view is always set corresponding to the focal length set in the zoom lens. 
     Another aspect of the invention will be known from the detailed description of the invention with reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view showing the appearance of a camera capable of trimming photographing according to the embodiments of the invention. 
     FIG. 2 is a top view of a camera capable of trimming photographing shown in FIG.  1 . 
     FIG. 3 is a perspective view for explaining the principal part of the configuration of a photographing optical system and a finder optical system according to a first embodiment; 
     FIGS.  4 ( a ) and  4 ( b ) are diagrams for explaining the relationship among the turning angle of a zoom cam, the focal length of a zoom lens and the angle of view of the finder optical system according to the first embodiment; 
     FIGS.  5 ( a ) and  5 ( b ) are diagrams for explaining the relationship among the turning angle of a zoom cam, the focal length of a zoom lens and the angle of view of the finder optical system according to a second embodiment; and 
     FIG. 6 is a diagram for explaining the principal part of the configuration of a photographing optical system and a finder optical system according to a third embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments of the invention will now be described. The following embodiments are examples of implementing the invention and not restrictive. This camera is capable of automatically continuously performing the transition from the telephoto end in the normal photographing mode to the trimming photographic mode, that is, the photographing mode of being scheduled to print only a part of a photographing image plane in printing, and so constructed that at the time of transition from the normal photographing area to the trimming photographing area, the angle of view (magnification) of the finder is continuously varied not to give a feeling of physical disorder to a photographer. 
     First Embodiment 
     FIG. 1 is a front view showing the appearance of a camera according to one embodiment of the invention, and FIG. 2 is a top view thereof. In FIGS. 1 and 2, a camera  1  is provided with a front panel  2  and a rear cover  3 , and a zoom lens  4  constituting the photographing optical system is collapsibly arranged in the center of the panel  2 . 
     A zoom finder  5  capable of varying the finder magnification is disposed above the zoom lens  4 , a projection window  6  and a photo-detecting window  7  for measuring the object distance are arranged on the right side, and the left side thereof, respectively. The reference numeral  8  is a photometric part, and  9  is a flashlight emitting part. The flash light emitting part  9  is disposed enough apart from the zoom lens  4  to prevent the occurrence of a red eye phenomenon (in the case of flash photographing, the eyes of a person as an object come out red). 
     A main switch  11  for turning on and off the power supply, a rewind switch  13 , a zoom switch  14  and an exposure start switch  15  are provided on the top of the camera  1 . 
     The outline of operation of the camera will now be described. First, in the initial state where the power is applied to the camera, the normal photographing mode is set. In such a state, when the zoom switch  14  is operated, the zoom lens  4  constituting the photographing optical system and the finder lens constituting the finder optical system are driven so that the focal length of the zoom lens  4  is changed and the angle of view (magnification) of the finder  5  is changed interlocking with the driving of zoom lens  4 . 
     When the focal length of the zoom lens  4  reaches the end of the telephoto side in the normal photographing mode, continued operation of the zoom switch  14  to the telephoto side, automatically causes the transition to the trimming photographing mode. At this time, to continuously change the angle of view of the finder optical system, the zoom lens  4  is once moved to the wide angle side in the transition area mentioned later, so that the focal length is set to make the size of picture by trimming process coincide with the angle of view of the finder optical system. 
     Further, upon continued operation of the zoom switch  14  to the telephoto side, the focal length of the zoom lens  4  is moved to the telephoto side in the trimming photographing mode, and with the movement, the angle of view (magnification) of the finder  5  is also changed. 
     In the trimming-photographing mode, when the zoom switch  14  is operated to the wide-angle side, the focal length of the zoom lens  4  is moved from the telephoto side to the wide-angle side, and with the movement, the angle of view (magnification) of the finder  5  is also changed. When the focal length of the zoom lens  4  reaches the end on the wide-angle side in the trimming photographing mode, automatically the transition to the normal photographing mode occurs. At this time, to continuously change the angle of view of the finder optical system, the zoom lens  4  is once moved to the telephoto side in the transition area mentioned later, so that the real focal length corresponding to the angle of view of the finder optical system is set. 
     Upon continued operation of the zoom switch  14  further to the wide-angle side, the focal length of the zoom lens  4  is moved to the wide-angle side in the normal photographing mode, and with the movement, the angle of view (magnification) of the finder  5  is also changed. 
     FIG. 3 is a perspective view showing the principal part of the configuration of the photographing optical system and the finder optical system, and FIG. 4 is a diagram showing the relationship among the turning angle of a zoom cam ring for driving the zoom lens constituting the photographing optical system, the focal length of the zoom lens and angle of view of the finder optical system. The configuration of the photographing optical system and the finder optical system will now be described with reference to FIGS. 3 and 4. 
     In FIG. 3, the reference numeral  20  is a rectilinear lens barrel for holding the zoom lens  4 , the reference numeral  21  is a zoom cam ring, the structure of a known zoom lens is provided in the interior of the rectilinear lens barrel  20  and the zoom cam ring  21 , and when the zoom cam ring  21  is rotated by zooming operation, the rectilinear lens barrel  20  is moved so that a desired focal length is set in the zoom lens  4 . 
     The zoom cam ring  21  is driven by a zoom motor which is a driving source not shown, and the turning angle of the zoom cam ring  21  is detected by an encoder not shown to be used as focal length information on the zoom lens  4 . 
     The reference numeral  25  is a finder cam for driving finder lenses  28  and  29  mentioned later. The finder cam  25  is provided with a rack  25   a  formed on the lower surface thereof, on the other hand, a gear  21   a  is formed on the outside of the zoom cam ring  21 , and interlocking gears  22   a,    22   b  and the interlocking gears  23   a,    23   b  are disposed between the gear  21   a  and the rack  25   a.    
     The finder cam  25  is provided with cam grooves  26  and  27  for driving the finder lenses  28  and  29 , on the other hand, the finder lenses  28  and  29  are respectively held on the lens holding members  28   a  and  29   a,  and the lens holding members  28   a,    29   a  are held by a guide shaft  30  to be freely moved forward and backward. The projections  28   b  and  29   b  provided on the lens holding members  28   a  and  29   a  are respectively fitted in the cam grooves  26  and  27 . 
     When the zoom cam ring  21  is rotated by zooming operation, the rotation is transmitted through a gear  21   a  and interlocking gears  22   a,    22   b  and  23   a,    23   b  to the rack  25   a  of the lower surface of the finder cam  25  to move the finder cam  25  in the directions of arrows (a) and (b) (opposite direction to the direction of the arrow (a). The movement in the directions of the arrows (a) and (b) of the finder cam  25  is transmitted through the projections  28   b  and  29   b  fitted in the cam grooves  26  and  27  to the lens holding members  28   a  and  29   a,  whereby the finder lenses  28  and  29  are moved to the positions corresponding to the focal length set in the zoom lens  4 , and the magnification of the finder corresponding to the focal length of the zoom lens  4  is set in the finder. 
     The relationship among the turning angle of the zoom cam ring for driving the zoom lens constituting the photographing optical system, the focal length of the zoom lens and the angle of view of the finder optical system will now be described with reference to FIGS.  4 ( a ) and  4 ( b ). 
     FIG.  4 ( a ) is a diagram showing the relationship among the turning angle of the zoom cam ring, the real focal length of the zoom lens and the angle of view of the finder optical system, in which the turning angle of the zoom cam ring  21  is used to enter the horizontal axis, and the focal length of the zoom lens  4  and the angle of view of the finder optical system are used to enter the vertical axis. 
     In FIG.  4 ( a ), the reference sign A designates a normal photographing area, C designates a trimming photographing area, and B designates a transition area. The reference sign L is a line showing the change of the real focal length of the zoom lens, and the reference sign F is a line showing the change of angle of view of the finder optical system. 
     FIG.  4 ( b ) is a development for explaining the cam groove of the zoom cam ring  21 , the reference numeral  41  is a cam groove, the reference numeral  51  is a cam follower provided on the rectilinear lens barrel, which is engaged with the cam groove  41 . The cam groove  41  is formed by a first cam groove  41   a  corresponding to the normal photographing area A, a second cam groove  41   c  corresponding to the trimming photographing area C, and a cam groove  41   b  of the transition area B connecting the first cam groove  41   a  and the second cam groove  41   c,  and when the zoom cam ring  21  is turned (moved in the lateral direction in FIG.  4 ( b )), the cam follower  51  is moved in the directions of arrows T and W (vertical direction in FIG.  4 ( b )) so that the focal length of the zoom lens  4  is changed. In the transition area B, the photographing mode is switched from the normal photographing mode to the trimming photographing mode. 
     When the cam follower  51  is put in the position (p) of the first cam groove  41   a  corresponding to the normal photographing area A, the focal length of the zoom lens  4  is set to the maximum wide angle position at the end on the wide angle side. When the zoom cam ring  21  is turned from such a state by zooming operation, the cam follower  51  moved toward the telephoto side in the first cam groove  41   a  so that the focal length of the zoom lens  4  is changed to the telephoto side. In the position (q), it is set in the maximum telephoto position. 
     When the zooming operation is further performed, the cam follower  51  is moved from the position (q) in the cam groove  41   b  of the transition area B to reach the position (r), and in the meantime, the real focal length of the zoom lens  4  is changed to the wide-angle side. This is for making the focal length of the zoom lens come to the focal length of the zoom lens  4  in the trimming photographing mode. 
     When the zooming operation is further performed, the cam follower  51  is moved from the position (r) toward the telephoto side in the second cam groove  41   c  corresponding to the trimming photographing area C, so that the focal length of the zoom lens  4  is changed to the telephoto side. In the position (s), it is set in the maximum telephoto position in the trimming photographing mode. 
     As clear from the above configuration, though the focal length of the zoom lens  4  of the photographing optical system is continuously changed by rotation of the zoom cam ring  21 , at the time of switching from the normal photographing mode to the trimming photographing mode, the focal length of the zoom lens  4  is once changed from the end on the telephoto side in the normal photographing mode to the wide angle side. This is for making the angle of view to be printed at a switching point in the trimming photographing mode approach the angle of view of photographing at the end on the telephoto side in the normal photographing mode, whereby at the time of transition from the normal photographing mode to the trimming photographing mode, the angle of view of the finder is kept from suddenly changing. 
     On the other hand, when the zoom cam ring  21  is turned, simultaneously the finder lenses  28 ,  29  are also continuously varied in magnification so that switching can be continuously and easily executed without a feeling of physical disorder. 
     In this configuration, in the transition area B of switching from the normal photographing mode area to the trimming photographing mode, the substantial focal length and the angle of view of the finder do not agree, so photographing may be inhibited. 
     Second Embodiment 
     In the described first embodiment, switching from the normal photographing mode to the trimming photographing mode or from the trimming photographing mode to the normal photographing mode can be performed by turning the zoom cam ring to continuously change the focal length of the zoom lens of the photographing optical system, but as described above, in the transition area of switching from the normal photographing area to the trimming photographing area, the substantial focal length and the angle of view of the finder do not coincide. 
     According to the second embodiment, the focal length of the zoom lens of the photographing optical system is changed in stages by turning the zoom cam ring in the first embodiment to cause a stepped zoom, whereby a mismatch portion between the substantial focal length in the transition area and the angle of view is avoided not to give a feeling of physical disorder in camera operation. 
     FIGS.  5 ( a ) and  5 ( b ) are diagrams for explaining the relationship among the turning angle of the zoom cam ring, the real focal length of the zoom lens and the angle of view of the finder optical system in the second embodiment. The configurations of the photographing optical system and the finder optical system are not different from those of the first embodiment shown in FIG. 3, and the general configuration of the camera is not different from that of the first embodiment shown in FIGS. 1 and 2, so the description is omitted. 
     FIG.  5 ( a ) is a diagram showing the relationship among the turning angle of the zoom cam ring, the real focal length of the zoom lens and the angle of view of the finder optical system, in which the turning angle of the zoom cam ring  21  is used to enter the horizontal axis, and the real focal length of the zoom lens  4  and the angle of view of the finder optical system are used to enter the vertical axis. 
     In FIG.  5 ( a ) the reference sign A designates the normal photographing area, C designates the trimming photographing area, and B designates the transition area. The reference sign L shows the change of real focal length of the zoom lens and F is a line showing the change of angle of view of the finder optical system. 
     As the stepped zoom is adopted, the focal length of the zoom lens of the photographing optical system is determined depending on the turning angle (a), (b), (c), (d), (e), (f), (g) of the zoom cam ring  21 . 
     FIG.  5 ( b ) is a development for explaining the cam groove of the zoom cam ring, which is not different from that of the first embodiment, so the same reference numerals designate the same members. In FIG.  5 ( b ), the reference numeral  21  is a zoom cam ring,  41  is a cam groove of the zoom cam ring  21 , the reference numeral  51  is a cam follower provided on the rectilinear propagation lens barrel, which is engaged with the cam groove  41 . 
     The cam groove  41  is formed by a first cam groove  41   a  corresponding to the normal photographing area A, a second cam groove  41   c  corresponding to the trimming photographing area C, and a cam groove  41   b  of the transition area B connecting the first cam groove  41   a  and the second cam groove  41   c,  and when the zoom cam ring  21  is turned (moved in the lateral direction in FIG.  5 ( b )), the cam follower  51  is moved in the directions of arrows T and W (vertical direction in FIG.  5 ( b )), so that the focal length of the zoom lens  4  is changed. The transition area B is an area where the photographing mode is switched from the normal photographing mode to the trimming photographing mode, and the zoom cam ring  21  is not stopped, which is an area independent of photographing. 
     As described above, the stepped zoom is adopted so that the rotation of the zoom cam ring  21  is stopped at angles of rotation (a), (b), (c), (d), (e), (f), (g), and in the other middle positions, it is not stopped. The configuration may adopt an arbitrary known configuration. 
     In the normal photographing mode, the rotation of the zoom cam ring  21  is stopped in positions (a), (b), (c), (d), (e), and the cam follower  51  is set in the appropriate position of the cam groove  41 . That is, when the cam follower  51  is put in a position (a) of the cam groove  41 , the focal length of the zoom lens is set to the maximum wide angle, and when the cam follower  51  is put in the position (e) of the cam groove  41 , the focal length of the zoom lens is set to the maximum telephoto. 
     When the zoom cam ring  21  is further turned, switching from the normal photographing mode to the trimming photographing mode is performed, the rotation of the zoom cam ring  21  is stopped in the positions (f), (g), and the cam follower  51  is set in the appropriate position of the cam groove  41 . That is, when the cam follower  51  is put in the position (f) of the cam groove  41 , the real focal length of the zoom lens is set to a first focal length (first telephoto) of the trimming photographing mode, and when the cam follower  51  is put in the position (g) of the cam groove  41 , the real focal length of the zoom lens is set to a second focal length (second telephoto) of the trimming photographing mode. The focal length of the second telephoto is larger than the focal length of the first telephoto and set to the maximum telephoto position. 
     On the other hand, when the zoom cam ring is rotated, simultaneously the finder lenses  28  and  29  are continuously varied in magnification to the telephoto side, the rotation of the zoom cam ring  21  is stopped in the positions (a), (b), (c), (d), (e), (f), (g), and in the other middle positions, it is not stopped, whereby the angle of view of the finder is also set to the angle of view corresponding to the substantial focal length in the positions (a), (b), (c), (d), (e), (f), (g). 
     Thus, in switching from the normal photographing mode to the trimming photographing mode, or switching inversely, a feeling of physical disorder is not caused, switching of the photographing mode can be also continuously executed easily, and in the transition area where the substantial focal length set in the zoom lens and the angle of view of the finder do not coincide, the zoom cam ring is not stopped and avoided not to be used for photographing. 
     Third Embodiment 
     In the described first and second embodiments, in order to set the finder magnification corresponding to the substantial focal length, the rotation of the zoom cam ring is transmitted to the finder cam, and in order to switch the photographing mode from the normal photographing mode to the trimming photographing mode or switch the same inversely by the rotation of the zoom cam ring, the finder cam is provided with a cam groove of a special form for driving the finder lens. 
     In the third embodiment, the turning angle of the zoom cam ring is detected to obtain the substantial focal length information set in the zoom lens, and the photographing mode information showing the normal photographing mode or the trimming photographing mode, according to the substantial focal length information and the photographing mode information, the finder focal length information to be set in the finder is computed, and according to the finder focal length information, the finder lens is driven to set the angle of view of the finder corresponding to the substantial focal length. 
     FIG. 6 is a diagram for explaining the configuration of the third embodiment. The general configuration of the camera is not different from that of the first embodiment shown in FIGS. 1 and 2, so the description is omitted. Further, the constitution of the rectilinear lens barrel for holding the zoom lens, the zoom cam ring, and a cam groove provided in the zoom cam ring and the relationship among the turning angle of the zoom cam ring, the real focal length of the zoom lens and the angle of view of the finder are not different from those of the first embodiment shown in FIGS. 3 and 4, so the description is omitted, and if necessary, FIGS. 3 and 4 should be referred. 
     In FIG. 6, the reference numeral  60  is a rectilinear lens barrel for holding the zoom lens  4 , the reference numeral  61  is a zoom cam ring, and a known zoom lens structure is provided in the interior of the rectilinear lens barrel  60  and the zoom cam ring  61 , and when the zoom cam ring  61  is rotated by zooming operation, the rectilinear lens barrel  60  is moved to set a desired focal length in the zoom lens  4 . 
     The zoom cam ring  61  is driven through a speed reducing gear mechanism  72  by a zoom motor  71  as a driving source, and the turning angle of the zoom cam ring  61  is detected by an encoder  73  to be input to a control circuit (formed by CPU)  75  as substantial focal length information. 
     On the other hand, the finder  81  is provided with a finder lens  82  for changing the angle of view of the finder in the finder optical system, and the finder lens  82  is driven through a speed reducing gear mechanism  84  by a finder motor  83  as a driving source. 
     In the above configuration, when the zoom switch  14  (See FIG. 2) is operated, the zoom motor  71  as a driving source is operated to rotate the zoom cam ring  61  through the speed reducing gear mechanism  72 . By the operation of the zoom switch  14 , the focal length corresponding to the turning angle of the zoom cam ring  61  at that time is set in the zoom lens. By continued operation of the zoom switch  14  to the telephoto side, the transition from the normal photographing mode to the trimming photographing mode can be caused. On the contrary, continued operation of the zoom switch  14  to the wide-angle side, causes the transition from the trimming photographing mode to the normal photographing mode. 
     On the other hand, the encoder  73  detects the turning angle of the zoom cam ring  61 , and the detection signal is input to the control circuit  75 . The control circuit  75  displays information showing the substantial focal length on a display device not shown according to the detection signal, and determines whether the photographing mode is the normal photographing mode or the trimming photographing mode according to the operation of the zoom switch  14 . 
     Further, the control circuit  75  computes the angle of view of the finder optical system according to the photographing mode and the substantial focal length information set by the zoom cam ring  61 , operates the finder motor  83  by designated number of revolution to attain the computed angle of view, and drives the finder lens  82  through the speed reducing gear mechanism  84 , whereby the angle of view corresponding to the photographing mode and the substantial focal length set in the zoom cam ring  61  is set in the finder optical system. 
     The control operation of the control circuit  75  can be simplified and facilitated by previously determining the necessary parameters such as the relationship between the turning angle of the zoom cam ring  61  and the photographing mode, the relationship between the turning angle of the zoom cam ring  61  and the focal length set in the zoom lens, the relationship between the angle of view of the finder optical system and the rotating speed of the finder motor  83 , and the like by experiments or the like and numerically representing the same to be stored in the ROM  76 . 
     Thus, the camera dispenses with the finder cam and its related structure, so that the mechanism part of the camera can be simply constructed. 
     According to the structure, as described above in detail, it will be apparent that with the camera, in switching the photographing mode, in the case of transition from the normal photographing mode to the trimming photographing mode, for example, the transition to the trimming photographing mode is caused by further performing the zooming operation from the maximum telephotograph position in the normal photographing mode, and in the case of transition from the trimming photographing mode to the normal photographing mode, the transition to the normal photographing mode is caused by further performing the zooming operation from the maximum wide angle position in the trimming photographing mode. Further, the finder can be always set to a suitable angle of view corresponding to the set substantial focal length. 
     Thus, the photographing mode can be simply switched, and since the finder is always set to a suitable angle of view, at the time of seeing through the finder, a feeling of physical disorder will not be given to a photographer by switching of the photographing mode.