This invention relates to photographing apparatuses such as lens-fitted film units and photo cameras of simple structures. More particularly, this invention relates to a photographing apparatus provided with a focusing position selecting mechanism which allows the photographer to set selectively two or more focusing points of a taking lens when taking a photo. Further more particularly, this invention relates to a finder mechanism which is suitable for application to products of simple structures provided with photographing functions, for example, such as lens-fitted film units and photo cameras of simple structures.
A lens-fitted film unit, which includes a photographing mechanism containing a taking lens and a shutter with an unexposed film roll previously loaded in the main body in the process of manufacture, is published, for example, in Japanese registered utility model publication No. 2,564,847. This lens-fitted film unit is so constituted as to wind up the exposed film into the cartridge each time a picture is taken, and so the user buys the unit and takes the unit itself to a photo developing shop to have it developed after the film roll has been finished. Therefore, the unit has gained wide market acceptance as a convenient and functional photographing product.
This lens-fitted film unit generally uses a single lens or two-piece lens structure in order to simplify the structure and bring down the cost of manufacture. This taking lens is fixed to the main body and focused on one particular focusing position. Therefore, the out-of-focus condition must be avoided by making the depth of field of the taking lens greater for objects which are not at the focused distance. However, various kinds of lens-fitted film units have recently been developed in respect to picture sizes and focal lengths of the taking lens, and so multifunctional products are much sought after.
In such diversified lens-fitted film units, it is required to properly set focusing positions in the process of manufacture in case it uses a long-focus taking lens, and so it is necessary to adopt a variety of schemes for the lens-focusing mechanism. For example, in the publication of Japanese laid-open patent publication Hei7-261069, a mechanism furnished with such a focusing mechanism as to focus a taking lens precisely and fix it to the setting position in the process of manufacture of a lens-fitted film unit furnished with a telephotographic lens, is disclosed. However, even in such a lens-fitted film unit, it is not possible to shift the focusing position to a plurality of focusing positions because the lens is fixed to the predetermined position. Taking such situations into consideration, it is preferred that lens-fitted film units and other cameras of simple structures can be applied to a plurality of different photographing situations such as normal photographing, and photographing of distant objects, and that they can take pictures properly focused while using a single taking lens or a two-piece-lens structure. A lens-fitted film unit, which is constituted to be able to take close-up photos in the proximity of within 60 cm with a reflex finder capable of moving in and out to allow the photographer to confirm the field and take photos of himself included in the field, is also suggested in the publication of Japanese laid-open patent publication Hei10-200834. The lens-fitted film unit disclosed in the publication can not be applied to a plurality of situations such as close-up photographing, normal photographing, and photographing of distant objects because the lens-fitted film unit does not have a plurality of focusing positions.
The present invention have been obtained in consideration of the above mentioned circumstances and has an object to provide a focus adjustment mechanism appropriate for use with a lens-fitted film unit or other simple structured cameras that use such a simple structured taking lens as a single-piece lens or two-piece lens structure, for example, and also adapt to photographing under a plurality of different conditions such as close-up photographing, normal photographing, and photographing of distant objects, and can take appropriately focused pictures in each case.
Another object of the present invention is to provide a lens-fitted film unit equipped with a simple structured lens mechanism that can adapt to photographing under a plurality of different conditions such as close-up photographing, normal photographing, and photographing of distant objects, and also with a finder that enable a photographer to check the photographing field from the front in close-up photographing and take pictures including he/herself in a composition.
In order to solve the above mentioned problem, a lens-fitted film unit in accordance with the present invention comprises a unit body having a photographing mechanism including a shutter, the unit body being formed with a cartridge chamber for storing a cartridge shell having a spool provided therein for rotation and retaining an end of a photo film strip, and a film roll chamber for storing a roll of unexposed photo film strip withdrawn out of the said cartridge shell, a cartridge shell and a roll of an unexposed photo film strip withdrawn out of the cartridge shell being charged in advance during manufacturing in the said cartridge chamber and the said film roll chamber, respectively, whereby an exposed film portion is taken up into the cartridge shell after each shot of photographing by rotating said spool, a selector member being provided for selectively determining a focus adjusting position either at a normal photographing position or at a close-up photographing position. The lens-fitted film unit is provided with a cylindrical lens holding member fixed to the unit body, a lens holding frame, in which a taking lens is fixed, arranged in the cylindrical lens holding member for rotation and axial movement in the direction of an optical axis, and a cam mechanism provided between the cylindrical lens holding member and the lens holding frame, the selector member being disposed in the camera body for movement between a predetermined normal photographing position and a close-up photographing position, the movement of the selector member causing the lens holding frame to rotate to thereby cause the lens holding frame to move along the optical axis by the action of the cam mechanism. The cam mechanism is provided with a cam member fixed to the cylindrical lens holding member and extending in the direction of the optical axis, the cam member being formed at a front end with a cam surface. On the back side of the lens holding frame, there are formed engaging legs that project backward along the optical axis and engage with the cam surface of the cam member. To depress the lens holding frame elastically onto the cam member, a spring is provided. The spring is located between an outer cover of the unit body and the lens holding frame. In a preferable structure, the spring is in the form of a coil spring, and the outer cover is formed around a photographing opening with a cylindrical spring support to be fitted into an end of the coiled spring. It is a preferable that the coil support has a diameter which is a little larger than the inner diameter of the coiled spring, so that the coiled spring is expanded radially to fit around the spring support. In this fashion, it will become possible that an end of the spring is engaged with the spring support elastically, and the spring is temporarily held on the outer cover, and transferred to an assembly site.
Engagement between the lens holding frame and the selector member is made by a pair of lens driving pins projecting backward from the selector member and a driven pin formed on the lens holding frame to project radially outward. The lens driving pins on the selector member are located with a space along the direction of movement of the selector member, while the driven pin on the lens holding frame occupies a position between the pair of the lens driving pins, and the selector member is driven by one of the pair of the driving pins when the selector member moves in one direction, while it is driven by the other pin when it moves in the other direction. The distance of the movement of the pair of the driving pins in the direction of the movement of the selector member is preferably 2 to 5 times as large as the diameter of the driven pins, so that, when the said selector member moves in one direction, by having one of the lens driving pins engaged with the driven pin, there is maintained between the driven pin and the said other lens driving pins a certain space corresponding to the difference of the distance between the pair of driving pins and the diameter of the driven pin. When the selector member moves in the opposite direction, the said other lens driving pin engages with the driven pin to drive the driven pin in the direction opposite to the said direction after the selector member has moved a distance corresponding to the space. More specifically, in each stroke of the movement of the selector member, after the selector member has made a predetermined distance of lost motion, either of the pair of lens driving pins on the selector member engages with the driven pin.
During assembly, the selector member is placed at one terminal end of the stroke of the movement. The lens holding frame is located at a position where the driven pin either engages with the lens driving pin located backside in terms of the direction of movement of the selector member in a succeeding stroke, or spaced apart for a distance from the lens driving pin smaller than the predetermined distance for the above mentioned lost motion. At this position of the cylindrical lens holding member, there is provided a retaining member for holding the driven pin on the lens holding frame to prevent the lens holding frame from dropping off from the cylindrical lens holding member. With the structure described above, the cylindrical lens holding member and the lens holding frame temporarily held thereon can be transferred to an assembly site in assembly. After assembly, when the selector member is first moved, the driven pin of the lens holding frame is disengaged from the retaining member, so that the selector member can be driven until it reaches the opposite terminal end of the movement stroke. When the selector member is thereafter moved in the opposite direction, after the selector member has moved by the distance of above mentioned lost motion, the other lens driving pin engages with the driven pin, and the selector member is driven until it reaches the first terminal end of the movement stroke. The position where the driven pin stops is different from that where the driven pin was held during assembling, so that when the selector member moves for a succeeding stroke, the driving pin engage the driven pin after the selector member has moved the predetermined distance for the lost motion. Therefore, after assembly, the driven pin is driven by a pair of driving pins without engaging the retaining member.
A selector member is located on the back side of the outer cover. The selector member is urged in one direction of movement by an elastic spring. On the selector member, a selector knob is formed, and the selector knob projects through a slot formed on the outer cover, and enables operation by fingers. In one specific form of the embodiment of the present invention, the front side of the selector knob is of such a configuration that it projects forwardly more than any other parts of the unit and contacts the packaging material most strongly. In this form of embodiment of the present invention, there is provided a flat area of a predetermined width on the top of the front side of the selector knob to increase the contact area with packaging material, to thereby prevent the knob from being worn out under vibrations during transportation. The width of the flat area is preferably 0.5 mm or more. In this flat, a recess of any desired shape can be formed, the recess having an effect of preventing shrinkage distortion of material in casting when selector knobs are formed with plastic material.
In accordance with features of the present invention, a lens-fitted film unit is further provided with a photographing field finder, and a reflexive mirror which is fixedly provided at a side of the photographing field finder to make it possible to observe a photographing field from the front side of the unit in close-up photographing. In the lens-fitted film unit according to the present invention, the focus position of the taking lens can be selected arbitrary, by moving the selector member between a 4 m focus position and a 60 cm focus position, for example. Also in another form, any one of 3 positions, for example, an infinite focus position, a 60 cm focus position can be selected arbitrary.
Moreover, in case of the 60 cm focus position for the close-up photographing is selected, a photographer can observe the photographing field by the reflexive mirror from the front side of the unit, and take pictures including the photographer himself in the photographing field.
In another form of the present invention, the selector member is formed integrally with a close-up field frame which is adapted to be located over the photographing filed finder to indicate the area of close-up photographing to compensate the parallax between the field of taking lens and the finder field when the selector member is at the close-up photographing position. This close-up field frame may be provided with a target mark that indicate the center of the photographing area when the selector member is at the close-up photographing position. Also, in the lens-fitted film unit of the present invention, a strobe flashing bulb is arranged in front of the unit body, and the selector member can be formed integrally with a light limiting portion that covers at least a part of the front side of the strobe flashing bulb to limit or restrict light emitted from the flashing unit.
According to another aspect of the present invention, there is provided a focus adjusting mechanism of a taking lens which comprises a cylindrical lens holding member fixed to a camera body and formed with a plurality of cam surfaces at circumferentially spaced places in a front side surface, and a lens holding frame provided in the cylindrical lens holding member for rotation and an axial movement in the direction of an optical axis and provided on outer peripheral portions with one or more pins which are adapted to be slidably engaged with said cam surfaces in the cylindrical lens holding member. The taking lens is fixed in the lens holding frame. The camera body has a lens holding frame holder of elastic material fixed thereto for holding the pins on the lens holding frame between the cam surfaces of the cylindrical lens holding member and the lens holding frame holder. A selector member is provided along the front side of the camera body for a sideward movement, the movement of the selector member causing the selector member to engage with the pins on the lens holding frame to thereby rotate the lens holding frame. As a result, the lens holding frame is caused to move in the direction of the optical axis by the engagement of the pins with the cam surfaces.
By using the focus adjusting mechanism of the taking lens according to the present invention, the focus position of a taking lens can be selected arbitrarily, for example, at either a 4 m position or a 60 cm position. In another form, selection at either an infinite focus position and a 4 m focus position may be possible, and if a cam surface is constructed with three steps, three arbitrarily selectable focus positions including, for example, an infinite focus position, a 4 m focus position, and a 60 cm focus position can be selected.
In another form of the present invention, a cylindrical lens holding member fixed to the camera body is formed with circumferentially spaced cams which are formed to penetrate from an inner circumference to an outer circumference of the lens holding member and have forwardly directed faces providing cam surfaces. The cam may be, for example, in the form of cam grooves. On the outer circumference of the lens holding frame, there are provided pins adapted to engage with the cams on the cylindrical lens holding member. The pins are inserted into the part where the cams are formed and project out of the outer surface of the cylindrical lens holding member. A selector member is arranged on the front side of the camera body so as to be movable sidewardly, the sideward movement causing the selector member to engage the pins on the lens holding frame to thereby rotate the lens holding frame. The engagement of the pins with the cam surfaces causes the lens holding frame to move in the direction of the optical axis. The selector member may be in the form of a frame member provided with an elongated opening in the middle portion, and in this case, the lens holding frame may be arranged to protrude from the opening of the frame member. The frame member is provided on the back side with lens holding frame driving pins protruding backward, and the lens holding frame driving pins engage with the pins on the lens holding frame and rotate the lens holding frame.
Also, the present invention provide a lens-fitted film unit equipped with a focus adjusting mechanism of taking lens above mentioned. Alternatively, the present invention provides, in one mode, a lens-fitted film unit, including a taking lens held in front of the unit body, a photographing mechanism having a shutter and provided in the body, the unit body having a cartridge chamber for storing a cartridge shell having a rotatable spool retaining an end of a photo-film strip, and a film roll chamber for storing a roll of unexposed photo-film withdrawn out of the cartridge shell, a cartridge shell and a roll of unexposed photo-film withdrawn out of the cartridge shell being charged during manufacture in the cartridge chamber and the film roll chamber respectively in advance, the spool being rotated to take up a frame of exposed film into the cartridge shell each time a shot is taken, said lens-fitted film unit being provided with the above mentioned taking lens focus adjustment mechanism. In this case, the unit body has a cylindrical lens holding member fixed thereto the cylindrical lens holding member being provided circumferentially spaced positions with cams which are formed by forwardly facing surfaces of positions penetrating from an inner circumference to an outer circumference. The taking lens is fixed to the lens holding frame, and the lens holding frame is arranged in such a way that it can rotate or move in the direction of the optical axis. The lens holding frame is provided with a pin on the circumference thereof, and the pin engages with the cam of the cylindrical lens holding member and projects out of the cylindrical lens holding member. In front of the camera body the selector member is arranged so as to be able to move sidewardly, and the sideward movement of the selector member causes the selector member to engage with the pin on the lens holding frame to thereby rotate the lens holding frame, the engagement of the pin with the cam causing surface causing the lens holding frame to move in the direction of the optical axis. The selector member may be in the form of a frame member having an elongated opening in the middle portion, and is arranged in such a way that from the opening of the frame member the lens holding frame projects out. In backside of the frame member, there are provided lens holding frame driving pins for engagement with the part of the pin on the lens holding frame that projecting out of the cylindrical lens holding member, to rotate the lens holding frame. In front of the unit body, a covering member may be attached so as to cover the frame member constituting the selector member.