Patent Publication Number: US-6711349-B1

Title: Camera assembly having a traveler and pivotable turret driven by an over-center mechanism

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 10/447,698, entitled: CAMERA ASSEMBLY HAVING TRAVEL STOP, filed May 29, 2003, in the name of Anthony DiRisio, which is hereby incorporated herein by reference. 
     Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 10/447,816; entitled: CAMERA ASSEMBLY HAVING FORWARD AND RETURN CAM SURFACES FOR A TURRET ON DIFFERENT PARTS, filed May 29, 2003, in the name of Anthony DiRisio, which is hereby incorporated herein by reference. 
     Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 10/447,701, entitled: CAMERA ASSEMBLY HAVING COVERGLASS-LENS ADJUSTER, filed May 29, 2003, in the name of Wayne Stiehler, which is hereby incorporated herein by reference. 
     Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 10/447,853, entitled: DEPLOYMENT APPARATUS FOR CAMERAS AND OTHER HAND-HELD DEVICES AND DEPLOYMENT METHOD, filed May 29, 2003, in the name of Michael Roger Allen, Anthony DiRisio, which is hereby incorporated herein by reference. 
     Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 10/447,702, entitled: CAMERA ASSEMBLY HAVING OVERCENTER BIASING OF TRAVELER AGAINST RESTS, filed May 29, 2003, in the name of Anthony DiRisio, which is hereby incorporated herein by reference. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/264,757, entitled: MULTIPLE POSITION LENS BARREL HAVING CAM CYLINDER WITH COMMONLY BIASED FIRST AND SECOND LENS CARRIERS, filed Oct. 4, 2002, in the name of Anthony DiRisio. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/324,488, entitled: CAMERA FRAME ASSEMBLY HAVING FOUR-BAR LINKAGE SHUTTER ACTUATOR, filed Dec. 20, 2002, in the name of Anthony DiRisio. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/324,966, entitled: CAMERA LENS MODULE HAVING RECYCLABLE LENS BARREL CAP, filed Dec. 20, 2002, in the name of Anthony DiRisio. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/327,503, entitled: EXTENDABLE LENS CAMERA HAVING MECHANICAL SHUTTER BLOCKING IN INTERMEDIATE LENS POSITION, filed Dec. 20, 2002, in the name of Anthony DiRisio. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/325,507, entitled: CAMERA FRAME ASSEMBLY HAVING SHUTTER THAT SLIDES FORWARD AND BACK WITH ZOOM LENS, filed Dec. 20, 2002, in the name of Anthony DiRisio, David J. Cornell. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/325,553, entitled: CAMERA FRAME ASSEMBLY HAVING SHUTTER ACTUATOR WITH TELESCOPING STRIKER AND METHOD, filed Dec. 20, 2002, in the name of David J. Cornell. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/317,490, entitled: CAMERA FRONT SEAL ASSEMBLY, filed Dec. 12, 2002, in the name of Anthony DiRisio. 
     Reference is also made to commonly assigned, co-pending U.S. patent application Ser. No. 10/326,450, entitled: CAMERA FRAME ASSEMBLY HAVING INDEPENDENTLY BACK-PIVOTING DRIVE HUB FOR IMPACT SHUTTER, filed Dec. 20, 2002, in the name of Anthony DiRisio, David J. Cornell. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to photography and photographic equipment and more particularly relates to camera assemblies having both a traveler and a pivotable turret driven by an over-center mechanism. 
     BACKGROUND OF THE INVENTION 
     One-time-use and inexpensive reusable cameras commonly use a fixed focus lens. This is limiting for the user. Some one-time-use cameras follow another approach in which only two focal lengths or focuses are available. U.S. Pat. Nos. 5,047,792 and 6,449,430 disclose one-time-use cameras, in which a pair of lenses are supported in a turret An over-center mechanism biases to the alternative positions. A shortcoming of this approach is that each lens is fully independent from the other, thus, a lens element cannot be shared. 
     An alternative approach is the use of a two position lens. U.S. Pat. No. 6,466,740 discloses a onetime-use camera having a two position lens. This camera pivots the lens using a slider and over-center mechanism. 
     Reusable cameras are known in which focal length is varied by telescoping a lens barrel to move a taking lens and, in addition or optionally, pivoting an internal additional lens into the optical path. U.S. Pat. Nos. 4,937,609; 4,525,050; 4,725,864; 5,005,038 and 5,765,049 disclose examples of such cameras. The taking lens, used by itself provides one focal length and used with the pivoting converter lens provides another focal length. The mechanisms are complex, as is the use of a converter lens in addition to a taking lens. 
     It would thus be desirable to provide a camera assembly in which a relatively simple, easy to use mechanism provides two lens positions by use of a turret and a movable lens barrel. 
     SUMMARY OF THE INVENTION 
     The invention is defined by the claims. The invention, in broader aspects, provides a camera assembly having a support that defines an optical axis. A traveler is movable along the optical axis between first and second positions relative to the support. A turret is disposed in and movable with the traveler. The turret has a primary aperture. The turret is pivotable relative to the traveler, between a first position in which the primary aperture is spaced from the optical axis, and a second position in which the primary aperture is aligned with the optical axis. The turret can have a secondary aperture that is aligned with the optical axis when the primary aperture is in the first position. An over-center mechanism is switchable between a first state, in which the over-center mechanism biases the traveler and turret into respective first positions, and a second state, in which the over-center mechanism biases the traveler and turret into respective second positions. 
     It is an advantageous effect of the invention that an improved camera assembly is provided, in which a turret and a movable lens barrel are driven between two positions, simply and easily, by an over-enter mechanism. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying figures wherein: 
     FIG. 1 is a partially exploded, front perspective view of an embodiment of the camera. 
     FIG. 2 is a front perspective view of the camera of FIG.  1 . 
     FIG. 3 is a partially exploded, front perspective view of the lens module of the camera of FIG.  1 . 
     FIG. 4 is an exploded front perspective view of the lens barrel of the camera of FIG.  1 . 
     FIG. 5 is a perspective view of the support of the lens module of FIG.  3 . 
     FIG. 6 is an exploded view of the support of FIG.  5 . 
     FIG. 7 is a side view of the support of FIG.  5 . The turret is also shown 
     FIG. 8 is a partially cutaway, perspective view of the lens module of the camera of FIG.  1 . The lens barrel is shown in an extended position. The turret is in a first position. The shutter is closed in FIGS. 8-10. 
     FIG. 9 is the same view as FIG. 8, but the lens barrel is shown in an intermediate position. The turret is in an intermediate position between the first and second positions. 
     FIG. 10 is the same view as FIG. 8, but the lens barrel is shown in the retracted position and the turret is in the second position. 
     FIG. 11 is a semi-diagrammatical top view of another embodiment of the camera. The lens barrel is shown in an extended position. 
     FIG. 12 is the same view as FIG. 11, but the lens barrel is shown in a retracted position. 
     FIG. 13 is a perspective view of a frame assembly of FIG.  1 . The frame assembly includes the frame, film transport, shutter, and turret. The shutter is in a closed position and the turret is in the second position. 
     FIG. 14 is a partial front view of the frame assembly of FIG.  13 . 
     FIG. 15 is the same view as FIG. 14, but the shutter is in the open position. 
     FIG. 16 is a partially cutaway side view of the lens barrel of the camera of FIG.  1 . 
     FIG. 17 is a rear perspective view of the lens barrel of the camera of FIG.  1 . The backer is not shown. The turret is in the first position. The shutter is not shown in FIGS. 17-19. 
     FIG. 18 is the same view as FIG. 17, but the turret is in the second position 
     FIG. 19 is a partially exploded, rear perspective view of the lens barrel the camera of FIG.  1 . 
     FIG. 20 is a simplified, exploded perspective view of another embodiment of the camera For clarity, only the over-center mechanism and related parts are shown. 
     FIG. 21 is a front view of the actuator base, support, and twist ring of the camera of FIG.  20 . The twist ring is shown in a wide angle position. 
     FIG. 22 is the same view as FIG. 21, but the twist ring is shown in the telephoto position. 
     FIG. 23 is a partial cross-sectional view of the deployment apparatus of FIG.  20 . The twist ring is in the telephoto position. 
     FIG. 24 is a front view of the camera frame, support, and actuator base of the camera of FIG.  20 . 
     FIG. 25 is a partial enlargement of the view of FIG. 24, showing the actuator base. 
     FIG. 26 is the same view as FIG. 25, except that the inner subunit of the actuator is also shown. 
     FIG. 27 is a front view of the actuator of the camera of FIG.  20 . The outer subunit of the actuator is shown by dashed lines. 
     FIG. 28 is a side view of the actuator of the camera of FIG.  20 . 
     FIG. 29 is a perspective view of the drive unit of the camera of FIG.  20 . 
     FIG. 30 is a front view of the drive unit of FIG.  29 . 
     FIG. 31 is a rear view of the drive unit of FIG.  29 . 
     FIG. 32 is a bottom view of the drive unit of FIG.  29 . 
     FIG. 33 is a front perspective view of the front travel stop of the camera of FIG. 1 . A portion of the coverglass is shown in dashed lines. 
     FIG. 34 is a partially cutaway, front perspective view of the lens module of the camera of FIG.  1 . 
     FIG. 35 is a partially cutaway, side view of the lens module of the camera of FIG.  1 . 
     FIG. 36 is a front perspective view of a frame assembly of another embodiment of the camera. A cover glass is shown separated from the lens module. 
     FIG. 37 is a front view of the frame assembly of FIG.  36 . 
     FIG. 38 is a partial cross-sectional view of another embodiment of the camera 
     FIG. 39 is a front view of the front lens holder and front lens of FIG.  38 . 
     FIG. 40 is a front perspective view of the front lens holder of another embodiment of the camera. 
     FIG. 41 is a top view of the shutter mechanism, film transport, and other related parts of the camera of FIG.  1 . The shutter is in the closed position. 
     FIG. 42 is the same view as FIG. 41, but the shutter is in the opened position. 
     FIG. 43 is a top view of the same features as FIG. 42, showing the shutter in the opened position. 
     FIG. 44 is a perspective view of the shutter and shutter driver of FIGS. 42-43. 
     FIG. 45 is a cross-sectional view of the frame assembly of FIG.  36 . The shutter is in an open position and is, thus, not visible in the figure. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The term “fixed” and like terms are used herein in the sense of a physical position or relationship that is in immobile and unchanging. The term “camera assembly” is used here to refer to a complete camera or an incomplete subunit of a camera that can be assembled with other parts to form a complete camera. The term “camera assembly” is inclusive of a complete one-time use camera and of a subassembly of a one-time-use camera. The usage of “camera” in the term “camera assembly” does not limit possible uses of a particular camera assembly. For example, a “camera assembly” that includes a lens system is inclusive of the usage of the same assembly as a component of a binoculars. For convenience, camera assemblies are generally designated by more descriptive names related to respective functions in a completed camera. 
     Turning now particularly to FIGS. 1-4, the camera  10  has a frame assembly  12  held within a shell having front and rear covers  16 , 18 . The frame assembly  12  includes a frame  20  to which a number of other camera components are attached. In the embodiment disclosed herein, one of those components is a lens module  22 , which includes a support  24  that is joined to the frame  20 . 
     The support  24  has a mount  26  and a guide  28  that is joined to the mount  26 . The support  24  can be permanently attached to the frame  20  or can be reversibly removable. The latter is convenient for the recycling of one-use-time cameras. The manner of attachment is not critical. The support  24  can be hooked to the frame  20  by hooks  30  and matching holdfasts (not shown). Other types of fasteners can also be used. The support  24  can also be adhered to the frame  20 , or held by friction fit, or by some other means. The frame  20  and support  24  or frame  20  and mount  26  can be made as a one-piece plastic casting, if desired, or can each be a one-piece plastic casting. 
     The camera  10  includes a capture unit  32  that captures and stores images. The type of capture unit  32  used is not critical. The capture unit  32  can capture images on photographic film. In that case, it is convenient if the frame  20  has a pair of opposed chambers (not separately identified in the figures). Film is wound from chamber to chamber across a capture plane (not shown). Film related features (not shown), such as a film transport  34 , can be provided in a manner well known to those of skill in the art. 
     With an electronic capture unit, the photographic film is replaced by an electronic imager (not shown). The imager is controlled by a control system that includes electronic memory. Captured images are stored in memory and can be manipulated by the control system. Features of such electronic capture units are well known to those of skill in the art. 
     A flash unit  36  and other camera components, well known to those of skill in the art, can also be included in the camera  10 . The flash unit  36  and other components are mounted to the frame  20  or held between the frame  20  and the covers  16 , 18 . 
     The support  24  defines an optical axis  38 . The guide  28  extends forward from the mount  26  along the optical axis  38  and encircles a central passage  40  aligned with the optical axis  38 . The term “encircles” and like terms are used in a broad sense that does not imply and is not limited to circular shapes, nor to structures without gaps or openings. In the embodiments discussed herein, the central passage  40  is generally circular in cross-section. It will be understood that like considerations apply to embodiments having like features of other shapes. The guide  28  has a rearward rim  42  that adjoins the frame  20  and a forward rim  44  opposite the rearward rim  42 . 
     The mount  26  is a forward-facing shallow cup (see FIGS. 3-7) that receives the guide  28 . A central opening  46  of the mount  26  can be bordered by a masking structure  48  that blocks unwanted light, so reducing flare. The guide  28  is snapped, adhered, or otherwise fastened in fixed relation to the mount  26 . The mount  26  and guide  28  are conveniently provided as two pieces, but can be provided as a single piece. 
     A lens barrel  50  is reversibly movable along the central passage  40 , in alignment with the optical axis  38 , from a retracted position, through a plurality of intermediate positions, to an extended position. It is preferred that the movement is rectilinear and that the guide  28  blocks rotation of the lens barrel  50  about the optical axis  38 . The lens barrel  50  can be disposed fully within the guide  28  in extended and retracted positions of the lens barrel  50  can protrude from the guide  28  in the extended position or in both extended and retracted positions. The invention is generally described herein in relation to an embodiment in which the lens barrel  50  is disposed completely within the guide  28 , in the extended and retracted positions. The front cover  16  encloses the guide  28 , except at a cover opening  52  aligned with the optical axis  38 . The lens barrel  50  can, alternatively, protrude from the guide  28  in the extended position or in both extended and retracted positions. In this case, the margin of the opening  52  in the front cover  16 , encircles the lens barrel  50  (not shown). 
     Referring now to FIGS. 8-12 and  33 - 35 , the extended and retracted positions of the lens barrel  50  are delimited by a front rest  54  and a rear rest  56 , respectively. The rests  54 , 56  are spaced apart from each other along the optical axis  38  and each border the central passage  40 . The lens barrel  50  has first and second contact surfaces  58 , 60 . In the extended position, the first contact surface  58  bears against the front rest  54 . In the retracted position, the second contact surface  60  bears against the rear rest  56 . 
     FIGS. 8-10 and  33 - 35  illustrate one embodiment of the front rest  54 . FIGS. 11-12 illustrate another embodiment. The rear rest  56  can be tie same or different, as desired. In the embodiments of FIGS. 8-10 and  33 - 35 , the front rest  54  is a portion of the inner surface of a travel stop  62   a  that is joined to the forward rim  44  of the guide  28 . (This embodiment is discussed below in detail.) 
     In the embodiment of FIGS. 11-12, the front rest  54  is a set of inwardly extending protrusions or posts  64  of the forward rim  44 . Bolts that extend through threaded openings in the forward rim  44  can be used instead to provide an adjustable rest, if desired. In FIGS. 11-12, the first contact surface  58  of the lens barrel  50  is flat. As shown in FIGS. 33-35, the first contact surface  58  can, alternatively, be provided on pins or other structures (discussed below in detail). One or both of the forward rim  44  and first contact surface  58  can have protrusions or the like or one or both can also be flat. 
     It is preferred that contact between the first and second contact surfaces  58 , 60  and the respective forward and rearward rims  44 , 42  is tripodal, that is, three point contact. For example, three protrusions  64  can be provided in the embodiment of FIGS. 11-12. Three point contact reduces any risk of wobbling and, in addition, reduces the areas in contact. This makes accurate part alignment simpler in production. 
     Referring to FIGS. 1-3 and  8 - 10 , in some embodiments, a twist ring  66  is mounted on the guide  28 . The twist ring  66  encircles the guide  28  or extends at least part of the way around the guide  28 . The twist ring  66  mechanically engages the lens barrel  50 , such that rotation of the twist ring  66  moves the lens barrel  50  along the optical axis  38  between the extended and retracted positions. The twist ring  66  is trapped in place axially by the forward rim  44  of the guide  28  and/or the travel stop  62   a  or other parts. (See FIGS. 5 and 8.) The mechanical coupling between the twist ring  66  and the lens barrel  50  is a cam-type extension-retraction mechanism. Other types of extension-retraction mechanism can be used. For example, the twist ring  66  and lens barrel  50  can be linked by a gear train, pins that ride in cam slots or grooves, or the like. 
     The lens barrel  50 , as shown in FIGS. 3-4, includes a traveler  68  that acts as a support structure and a cap  70  that closes the forward end of the traveler  68 . The traveler  68  and cap  70  can each be a one-piece plastic casting. In the illustrated embodiment, the traveler  68  includes a tracker  72  and has a crosswall  74  that extends in a direction perpendicular to the optical axis  38  and a circumferential outside wall  76  that encircles the crosswall  74 . The crosswall  74  has a central opening or primary aperture  78  that is aligned with the optical axis  38 . 
     In particular embodiments, the tracker  72  has three track followers  80  that extend outward relative to a main portion  82  of the lens barrel  50 . The track followers  80  can be equally spaced about the traveler  68  to help prevent the traveler  68  from canting relative to the support  24 . Each track follower  70  has a pair of spaced apart posts  84 . The twist ring  66  has a tracking portion  86  that receives the tracker  72  of the traveler  68  and constrains of the traveler  68 , such that the traveler  68  moves forward and backward along the optical axis  38  when the twist ring  66  is rotated between the rightward and leftward configurations. 
     The tracking portion  86  of the twist ring  66  is a set of internal tracks  88  that spiral about the optical axis  38 . Each track  88  receives a respective one of the track followers  80  of the traveler  68 . In particular embodiments, the tracks  88  are spiral ribs that extend toward the optical axis  38  from the circumferential wall  90  of the twist ring  66 . The tracks  88  are gripped between the posts  84  of the respective track followers  80 . Alternatively, tracks  88  can be grooves or pairs of parallel fences that receive track followers  80  configured to ride in the grooves or between the fences. The extension-retraction mechanism features of the lens barrel  50  and twist ring  66  also can be interchanged, for example, the posts  84  can be provided on the twist ring  66  rather than the lens barrel  50 . 
     The track followers  80  extend to the tracks  88  through corresponding slots  92  in the guide  28 . The slots  92  each extend parallel to the optical axis  38 . In illustrated embodiments, there are three slots  92  and three corresponding tracks  88 . The track followers  80  slide along the tracks  88  when the twist ring  66  is rotated. Since the track followers  80  are held by the slots  92  of the support  24 , this results in the lens barrel  50  traversing linearly inward or outward along the optical axis  38 . 
     The first and second contact surfaces  58 , 60  are parts of the traveler  68 . In the embodiment shown in FIGS. 33-35, the first and second contact surfaces  58 , 60  are opposed portions of the posts  84  of the track followers  80 . 
     In the embodiment of the FIG. 11-12, the first and second contact surfaces  58 , 60  are portions of the front and rear of the traveler  68 . In this embodiment, the twist ring  66  is not present The traveler is, instead, reciprocated using a pivotable link  202  that receives a post  208  of the traveler  68 . The link  202  is joined, in fixed (immobile) relation to a rotatable knob or like feature (not shown) that is accessible from the exterior of the camera. The tracker  72  and slots  92  of the guide  28  can be provided as earlier described, or in simplified form. In this embodiment, the tracker only provides guidance and centering of the traveler  68  during movement. Examples of simplifications are limiting the depth of the slots  92 , such that the slots  92  do not extend fully through the guide  28  and reducing the number of posts  84  in the track followers  80 . 
     In some embodiments herein, the lens barrel  50  is set up for use in only the retracted and extended positions and not the intermediate positions. A biaser  94  deters against stoppage of the lens barrel  50  in the intermediate positions, as discussed in detail below. Because of this, it is unnecessary for the traveler  68  to be maintained in a more than approximate alignment with the optical axis  38 , when the lens barrel  50  is in the intermediate positions. The guide  28  provides this approximate alignment. The guide  28  also retains the traveler  68  in close alignment with the optical axis  38  in the retracted and extended positions. 
     Referring particularly to FIGS. 33-35, the track followers  80  are loosely held by the tracks  88  of the twist ring  66  and the slots  92  of the guide  28 . The twist ring  66  fits loosely on the guide  28 . The positions of each track follower  70  are determined by the respective track  88  and slot  92 . The loose fit of the track followers  80  in the slots  92  and the twist ring  66  on the guide  28 , allows angular misalignment of of the twist ring  66  and traveler  68  relative to the optical axis  38  during movement of the traveler  68  between the retracted and extended positions. The loose fit is advantageous, in that looser tolerances reduce manufacturing costs. This is not problematic, because canting of the traveler  68  is limited to intermediate positions of the traveler  68  between the retracted and extended positions. In the retracted and extended positions, the respective contact surface  58 , 60  of the traveler  68  is in engagement with the respective rest  54 , 56 . As earlier noted, three point contact between the rest  54 , 56  and respective contact surface  58 , 60  can be provided to further help eliminate the risk of tilting of the traveler  68  relative to the guide  28 . 
     The loose fit of the twist ring  66  and tracks  88  does allow some other traveler  68  movement. The track followers  80  can pivot slightly back and forth about the optical axis  38  relative to the respective slots  92  of the guide  28 . This can be ignored. Optical elements (discussed below) provided in the traveler  68  can have uniform properties relative to rotation about the optical axis  38 . The traveler  68  also has a risk of mispositioning in a direction parallel to the optical axis  38 . This parallel mispositioning can be limited by close dimensioning of outer wall  76  of the traveler  68  and the central passage  40  of the guide  28 . This can be done throughout the guide  28  or only at the front and rear and of the guide  28  where the traveler  68  enters the retracted and extended positions, respectively. 
     Referring now to FIGS.  4  and  13 - 19 , a turret  96  is disposed in and supported by the traveler  68 . The turret  96  rides with the traveler  68  between the retracted and extended positions. The turret  96  has one or two rear optical element seats  98 , 99 . Each seat  98 , 99  surrounds an aperture  100 , 102 . The turret  96  is pivotable, relative to the traveler  68 , about a pivot axis  104  that extends through the traveler  68  and is parallel to the optical axis  38 . The pivoting of the turret  96  is between a first position, shown in FIGS. 8 and 17, in which one of the apertures  100  is in alignment with the optical axis  38 , and a second position, shown in FIGS. 10 and 18, in which that aperture  100  is spaced from the optical axis  38  and a second aperture  102 , if present, is aligned with the central opening  78  of the traveler  68 . 
     In the embodiments disclosed herein, the turret  96  is located between the outer wall  76  of the traveler  68  and the optical axis  38 . This is advantageous for one-time-use cameras, since the outer wall  76  can protect the turret  96  from impacts and the like, during stages of recycling in which the front and rear covers  16 , 18  have been removed. 
     A front lens element  106  is mounted in the traveler  68  over the central opening  78 , in alignment with the optical axis  38 . Optionally, one or more additional optical elements (not shown) are located within the traveler  68 . In the embodiment disclosed herein, a first turret lens element  108  is mounted in a first rear optical element seat  98  over the first rear aperture  100 . A second turret lens element  110  can be mounted in a second rear optical element seat  99  over the second rear aperture  102 . The front and rear lens elements  106 , 108 , 110  and other lens elements (if any) together comprise a taking lens system that directs light to the capture plane. The rear lens elements  108 , 110  are aligned with the optical axis  38  in first and second positions of the turret  96 , respectively. 
     In the embodiment shown in FIGS. 33-35, the front lens element  106  and first turret lens element  108  are a first doublet lens and the front lens element  106  and second turret lens element  110  are a second doublet lens. The first and second rear lens elements  108 , 110  have different optical powers, providing for different focusing distances or different focal lengths of the first and second doublet lenses Other optical elements can be provided in addition to or in place of one or both of the turret  96  lens elements. 
     Referring now to FIGS. 4,  13 - 16 , and  41 - 44 , in some embodiments, a shutter  112  is disposed in the traveler  68  between the crosswall  74  and the turret  96 . The shutter  112  moves forward and back along the optical axis  38  with the traveler  68 . The shutter  14  is normally in a closed state in which the shutter  14  tightly covers the central opening  76 . 
     The shutter  112  is part of a shutter mechanism  114  that includes a shutter release  116  that is mounted to the frame  20 . The shutter release  116  is releasable by the user to momentarily open the shutter  112 . A single leaf impact shutter is shown that pivots, relative to the traveler  68 , between a closed position, in which the central opening  76  is blocked, and an open position, in which the central opening  76  is opened. 
     The shutter  14  is driven by a shutter drive lever  118 . The shutter drive lever  118  is charged by the film transport  34  to a charged state. Digital cameras can use the same shutter driven by a simpler mechanism or can use another mechanical shutter or can use internal electronics of the imager and control system that act as a shutter, depending upon the imager used. 
     The film transport  34  includes a combined thumbwheel and metering wheel  120  that is mounted for rotation adjacent a top corner of the frame  20 . A portion of the wheel  120  extends beyond the rear cover  18  and is accessible to the camera operator. If desired, rather than being driven directly by the user, the wheel  120  can be driven by a winding knob, lever, electric motor or other like device. 
     Photographic film  122  is initially wound in a coil in one film chamber (not shown) and extends across the capture plane (indicated by arrow  121  in FIG. 41) to another film chamber (not shown), in which an end of the film  122  is held by the spool  124  of a film cartridge  76 . The wheel  120  has a key (not shown) that couples the wheel  120  to the film cartridge spool  124 , such that forward rotation of the wheel  120  causes the film  122  to be wound into the cartridge  76  and advanced past the capture plane  121 . An anti-backup pawl  126  is resiliently biased against an edge of the wheel  120  to prevent rotation in a reverse direction. 
     A film metering sprocket  128  has a sprocket shaft  130  that is pivotably supported by the frame  20 . The sprocket  128  engages perforations in the film  70  and is rotated through a complete revolution each time the film  70  is advanced by a distance corresponding to one film frame. 
     An actuator disk  132  and a charging cam  134  are made in one piece with the sprocket  128  or are assembled with the sprocket  128  so as to remain in fixed (immobile) relation. The actuator disk  132  has a otherwise continuous circumference interrupted by a notch  136 . The charging cam  134  has a spiral surface on one side. 
     A film metering lever  144  is supported for pivotal movement by the frame  20 . The metering lever  144  is biased by a coil spring  146  in an activating direction. The metering lever  144  has a first arm  148  ending in a tooth and a second arm  150  having a pawl. When the toothed arm  148  of the metering lever  144  is received in the notch  136  of the actuator disk  132 , the pawl arm  150  of the metering lever  144  engages the toothed rim of the wheel  120  temporarily blocking advancement of the film  122 . 
     The shutter release  116  includes a shutter button  138  that is located near the cantilevered end of a flexible arm  140  of the shutter release  116 . Adjacent the shutter button  138  the arm  140  has a vertical tab that carries a latch member  142 . 
     The shutter drive lever  118  is biased by a spring  152 . The shutter drive lever  118  has a tongue  154  that is engaged by the latch member  142  to hold the shutter drive lever  118  in a charged state in opposition to the spring  152 . The shutter drive lever  118  also has a cam follower finger  154  that is positioned so as engage the charging cam  134  of the film transport  34 . 
     A pair of tie bars  156 , 158  extend outward from the frame  20 . The first tie bar  156  is united with the shutter drive lever  116 , preferably the bar  156  and lever  116  are different portions of a one-piece casting. The tie bars  156 , 158  each have opposed first and second ends. The first ends are spaced apart from each other and are each pivotably joined to the frame  20 . A parallel bar  164  is pivotably joined to the second ends of the two tie bars  156 , 158 . The parallel bar  164  is spaced forward from the first ends and, can also be spaced forward from the frame  20 . A striker  166  is movable with and, preferably, joined to the parallel bar  164 . The striker can be modified to telescope as the traveler moves, if desired. 
     When the shutter drive lever  118  is in the charged state and the camera  10  is in condition to make an exposure, as shown in FIG. 41, the tongue of the shutter drive lever  118  is engaged by the latch member  142 , which holds the shutter drive lever  118  in the charged condition in opposition to the spring  152 . Prior to this, during film advance, the sprocket  128  has been rotated into a position in which the toothed arm  148  of the metering lever  144  is in the notch  136  of the actuator disk  132 . This allows the metering pawl arm  150  to engage the wheel  120  under the influence of the spring. The cam follower finger of the shutter drive lever  118  is out of contact with the charging cam  134 . 
     When the photographer depresses the shutter button  138  to initiate an exposure, the shutter release  116  is released from a ready state to a released state. The shutter button  138  moves the latch member  142  out of engagement with the tongue of the shutter drive lever  118 , the shutter drive lever  118  is pivoted rapidly by the spring from the charged state to the discharged state. This causes the striker to impact a tang  168  of the shutter  112 , causing the shutter  112  to rotate from a closed state to an open state. The tang  168  is on an extension  170  of the shutter  112  that extends in a direction parallel to the optical axis  38  from the remainder of the shutter. The extension  170  provides for an overlap of the tang  168  and striker  166  when the traveler  68  is in the extended and retracted positions. The impacting of the tang  168  moves the shutter  112  away from the aperture exposing a light image on the capture plane. The aperture is uncovered momentarily. When the striker moves past the tang  168  of the shutter  112 , the shutter  112  returns to a closed state under the biasing of a shutter return spring  169 . 
     After the film exposure has been completed, the shutter drive lever  118  moves into engagement with a downwardly extending yoke  173  of the metering lever  144 . This causes the metering lever  144  to rotate to a deactivated position, by overpowering the weaker force exerted on the metering member by spring  146 . Accordingly, the metering pawl arm  150  is disengaged from the wheel  120  and the metering member tooth arm  148  is retracted from the actuator disc notch  136 . This allows the transport mechanism  34  to be operated to advance the film  122  to the next available frame. 
     When the photographer next rotates the wheel  120  forward, the film  122  is wound onto the spool  124 . This causes the metering sprocket  128  to rotate in the same direction. The charging cam  134  engages the finger  171  of the shutter drive lever  118  and rotates the latter back to a charged state. 
     A great variety of other suitable shutter mechanisms are well-known to those of skill in the art and are commonly used in currently available cameras. 
     Referring now to FIGS. 4,  8 - 10 , and  13 - 19 , the turret  96  has opposed front and rear surfaces  172 , 174 . The rear lens element or elements  108 , 110  are disposed against the rear surface  174 . The shutter  112  closely adjoins the front surface  172 . The turret  96  pivots against a set of standoffs  179 . Each standoff is part of the crosswall  74  of the traveler  68 . The standoffs  179  provide space between the crosswall  74  and turret  96  for movement of the shutter  112 . The shutter closely adjoins the crosswall  74  and front surface  174  of the turret  96  and can contact one or both. The standoffs are configured so as to support the traveler, without excessive friction. In the embodiment shown, the standoffs  179  include a rib  176  and two or more nubs  181  (best seen in FIG.  19 ). 
     A backer  178  is joined to the traveler  68 . The backer  178  moves with the traveler  68  relative to the support  24 . The turret  96  is trapped between the backer  178  and the crosswall  74  of the traveler  68 . The backer  178  is advantageous for one-time-use cameras, in which in the lens module  22  may be separated from the remainder of the camera  10 , during recycling, since the backer  178  helps protect the turret  96 . against damage. 
     Referring now to FIGS. 5-10 and  16 - 19 , the turret  96  has a cam follower  180  that extends into a cam slot  184  and moves along the cam slot  184  between opposed ends  186 , 188 . The turret  96  pivots to the first position when the cam follower  180  moves to the first end  186  of the can slot  184 . The turret  96  pivots to the second position when the cam follower  180  moves to the second end  188  of the cam slot  184 . 
     The pivoting of the turret  96  is mechanically synchronized with the axial movements of the traveler  68 , such that the lens barrel  50  is in a first configuration, when the cam follower  180  is disposed in the first end  186 , and a second configuration, when the cam follower  180  is disposed in the second end  188 . The traveler  68  is in the retracted position in the first configuration, and the extended position in the second. 
     In particular embodiments of the invention, the support  24  has a forwardly extending cam finger  190 , which has a first cam surface  192 . The guide  28  has a cam notch  194  that receives the cam finger  190 . The cam notch  194  has a second cam surface  196 . The first cam surface  192  is inclined relative to an imaginary line parallel to the optical axis  38 . The second cam surface  196  is parallel to and spaced from the first cam surface  192 . The cam surfaces  192 , 196  together define the cam slot  184  and first and second opposed ends  186 , 188 . The provision of the first and second cam surfaces  192 , 196  on a support  24  and guide  28  that are separate pieces joined together is advantageous for simplifying the molding of the support  24  as a one-piece plastic casting and the guide  28  as another one-piece plastic casting. 
     Referring now mainly to FIGS. 20-23, the biaser  94  urges the first contact surface  58  toward the front rest  54 , when the lens barrel  50  is in the extended position, and urges the second contact surface  60  toward the rear rest  56 , when the lens barrel  50  is in the retracted position. It is preferred that the biaser  94  also urges the lens barrel  50  away from the intermediate positions and toward the nearer of the extended and retracted positions. The biaser  94  also acts on the turret  96 , directly or indirectly, and urges the cam follower  180  of the turret  96  toward the first and second ends  186 , 188  of the cam slot  184  and away from a continuum of intermediate position between the ends  186 , 188  of the cam slot  184 . As earlier noted, this is in coordination with movement of the traveler  68 . 
     The biaser  94  includes one or more coordinated over-center mechanisms. It is highly preferred that the over-center mechanism or mechanisms driving the lens barrel  50  provide a high degree of biasing and a rapid turnover between a first state, in which biasing is in a forward direction, and a second state, in which biasing is in a reverse direction. An increase in biasing up to the time of turnover is preferred. 
     Referring now to FIGS. 16-19 in particular embodiments, the biaser  94  includes a turret spring  197  that biases the turret  96  into the first and second positions shown, for one embodiment, in FIGS. 8 and 17, and  10  and  18 , respectively. The turret spring  197  biases the turret  96  away from intermediate positions like the one shown in FIG.  9 . The turret spring  197  also continuously biases the turret  96  against said traveler  68 . In the embodiment shown in FIGS. 16-19, the turret spring  197  has a first end  199  that bears on the turret  96 . A second end  195  is attached to the crosswalk  74  of the traveler  68  and is bifurcated to provide space for the cam follower  180 . 
     In the embodiment shown in FIGS. 11-12, the biaser  94  has an over-center mechanism  198  that has a link  202  pivotably joined at an inner end  209  to the support  24 . The support  24  has a post  206 . The link  202  has a hole that fits over the post  206 . The other end  211  of the link  202  is slidably joined to the traveler  68 . The traveler  68  has an upwardly extending post  208 . The outer end  211  of the link  202  has an opening  210  shaped like a long oval, but having a slight dogleg at an inner end  212  of the opening  210 . The post  208  is movable along the opening  210  between the inner end  212  and an outer end  214 . 
     In this embodiment, the support  24  has a flange  216  that protrudes forward from the remainder of the support  24 , between the two ends  205 , 206  of the link  202 . The over-center mechanism  198  has an over-center spring  200  having a loop at either end. A first loop is a joined to the flange  216 . The second loop is joined to the link  202  between the two ends  209 , 211  of the link  202 . The over-center spring  200  is characterized by rapid turnover and an increase in biasing up to turnover. 
     The link  202  is movable between a retracted position and an extended position, in tandem with the movement of the lens barrel  50 , between respective retracted and extended positions. The flange  216 , to which the over-center spring  200  is attached, is forward of the centerline of the link  202 , in the retracted position and rearward of the centerline of the link  202  in the extended position. During the movement between the retracted and extended positions, the post  208  of the traveler  68  moves along the opening  210  between the two ends  205 , 206 . The over-center mechanism  198  is switched between retracted and extended positions by rotating the lens barrel  50  directly or indirectly via a mechanically coupled part. 
     Referring now to FIGS. 8-10 and  17 - 32 , in other embodiments, the biaser  94  also includes an over-center spring  200  having a loop  201 , 203  at each end. One of the loops  201  is joined to the twist ring  66 . The other loop  203  is joined to a boss  29  that is part of the support  24  or frame  20 . The loops are held by knobs  205 , 207  that each extend outward from a respective part The knobs  205 , 207  can have notches or the like (not shown) to help hold the loops  201 , 203 . The spring  200  held by the support  24  can, alternatively, be joined to the frame  20  or another non-moving part. 
     The over-center spring  200  is part of a deployment mechanism  218 . The deployment mechanism  218  has an actuator  220  having a grip  222  and a slide  224 . The grip  222  is accessible from the outside of the body and can include a raised handhold (as shown) and/or one or more features for easier manipulation by the user, such as knurling or other texturing. The grip  222  is movable back and forth within a recess  226  in the front cover  16 . The grip  222  has a connector  228  that protrudes through an opening  230  in the recess  226 . The opening  230  can be centered within the recess  226  and is fully overlapped by the grip  222 . This provides light locking. The travel of the grip  222  is limited by the length of the recess  226 . Travel can be limited by the length of the opening  230  within the recess  226 , but this may be esthetically unappealing, in that the fit of the grip  222  in the cover  16  may look sloppy to the user. 
     The actuator  220  is disposed against an actuator base  232  that adjoins the guide  28  of the lens module  22 . The actuator base  232  can be part of the frame  20 , or a separate piece, or integral with the guide  28  or mount  26  of the support  24 . For example, the actuator base  232  and guide  28  can be parts of a one-piece plastic casting. This is convenient in that the alignment of the deployment apparatus with the lens barrel  50  is, to a large extent, a function of the physical positioning of the actuator base  232  alongside the guide  28 . In particular embodiments, the guide  28  is hooked to the mount  26  and the actuator base  232  and mount  26  are both hooked to the frame  20  to reduce the risk of flexure of one part relative to another during use. 
     The slide  224  of the actuator  220  rests against the actuator base  232  and is movable reciprocally on the actuator base  232 . The slide  224  can have a stepped shape (see FIG.  28 ), in which a lower step  236  rides in a trough  238  in the actuator base  232 . A rib  240  extends outward from the lower step  236 . The rib  240  extends transverse to the direction of movement of the actuator  220 . The rib  240  has a pair of opposed faces  239 , 241 . A transition  242  adjoins the lower step  236  and slopes upward to an upper step  244 . The upper step  244  rides against a shelf  246  of the actuator base  232 . The shelf  246  and trough  238  are flat where the slide  224  is in contact, but could be modified to reduce friction. The region  247  of the actuator base  232  between the trough  238  and the shelf  246  is cutaway to provide clearance for the transition  242 . 
     The actuator base  232  includes a pair of flanges  248 , 250 . (See FIGS. 26-28.) The first flange  248  overlaps a groove  252  adjoining the trough  238  in the actuator base  232 . A similar groove  254  adjoins the sloped region  247  of the actuator base  232 . The second flange  250  overlaps the second groove  254 . The lower step  236  of the slide  224  has a tang  256  that is shaped so as to fit in first groove  252 . The upper step of the slide  224  has a similar tang  257  that fits in the second groove  254 . The ends of the trough  238  is open and the slide  224  can flex slightly. This allows the slide  224  to be slid under the flanges  248 , 250  during assembly of the camera  10 . 
     A pawl-arm  258  has a flexible arm  260  that terminates in a pawl  262 . The pawl-arm  258  is joined to the upper step  244  of the slide  224 . A detent rib  264  protrudes outward from the actuator base  232 . The pawl-arm  258  rides against the detent rib  264  and resiliently biases the actuator  220  toward the primary and secondary positions and away from intermediate positions between the primary and secondary positions. The pawl-arm  258  and detent rib  264  together provide an actuator over center mechanism  198   a . This over-center mechanism  198   a  acts in concert with a second or drive over-center mechanism  198   b  that includes the over-center spring  200 . 
     The upper step  244  of the slide  224  has a fitting  266  that receives the connector  228  of the grip  222 . In the embodiment shown, the grip  222  is snap fit into a hole in the upper step of the slide  224 . This is convenient, because the grip  222  is held in place without the use of additional parts and the camera  10  is easy to assemble. Alternative approaches for attaching parts are well-known to those of skill in the art. 
     The actuator base  232  has an outwardly extending post  268  and a drive unit seat  270 . The drive unit seat  270  and post  268  are offset from each other. A drive unit  272  is seated in the drive unit seat  270  and is pivotable about a drive axis  274  (shown in FIG. 20) that extends through the seat  270 . The drive unit  272  and drive unit seat  270  can fit in the manner of a hub and axle; however, it is convenient to provide a snap fit, in which the drive unit seat  270  is a rimmed hole and the drive unit has a snap connector  273 , as shown in some of the figures. 
     The drive unit  272  has a gear wheel  276  having circumferential teeth. A post  277  extends upward near the periphery of the gear wheel  276 . The drive unit  272  has a pair of downwardly extending stops  278 , 280  that extend downward from the gear wheel  276 , near the periphery of the gear wheel  276 . The post  268  and stops  278 , 280  can be radially positioned differently, but the peripheral position shown maximizes drive unit  272  movement, for a given gear wheel size. The posts  268  and stops  278 , 280  can be moved further out radially on extensions (not shown), but this may complicate assembly of the device. The gear wheel  276  overlaps the slide  224 . This reduces space requirements of the deployment apparatus  218 . 
     The stops  278 , 280  extend downward from the gear wheel  276 , to an extent that the stops  278 , 280  can interfere with the rib  240  during movement of the actuator  220 . The stops  278 , 280  are spaced apart from each other. This separation can be varied but is, desirably, greater than 180 degrees in the directions of travel of the drive unit  272  (discussed in detail below). In the deployment apparatus shown in FIGS. 20-32, this separation of the stops is 270 degrees in the direction of movement of the drive unit  272 . Angles of less than 180 degrees can be used, but for a given travel of a deployable component, require use of a larger gear wheel  276 . This decreases the compactness that is a benefit of the deployment apparatus  218  described here. 
     In use, the gear wheel  276  does not have to have a complete circle of teeth. For example, in the embodiment of FIGS. 20-32, the teeth in the 90 degree arc between the two stops  278 , 280  are non-functional could be eliminated. A complete circle of teeth, although non-functional in the finished device, can be beneficial during assembly, since the drive unit  272  can be put in place in a random orientation and can then be rotated in either direction until a correct orientation is reached. The deployable component  218  is then assembled with the drive unit  272  after the correct orientation has been reached. 
     The twist ring  66  is toothed to match the movement of the drive unit  272 , that is, the teeth are complementary to the functional teeth of the drive unit  272 . 
     In the embodiment of FIGS. 20-32, the drive over-center mechanism  198   b  is mounted to the actuator base  232  and the drive unit  272 . The drive over-center mechanism  198   b  has an over-center spring  200  having a loop  201 , 203  at the end of each of two opposed arms. The first loop  201  is fitted over the post  277  of the drive unit  272 . A second loop  203  is fitted over the post  268  of the actuator base  232 . The over-center spring  200  biases the drive unit  272 , enmeshed twist ring  6 , and traveler  68  toward the orientations shown in FIGS. 21 and 22 and away from in-between orientations. 
     Other types of over-enter mechanisms can be used in place of those disclosed here. For example, the pawl-arm  258  and detent rib  264  can be replaced by an over-center spring like the ones illustrated. (Posts can be added to the actuator base  232  and slider  224  to hold respective loops of the over-center spring.) 
     The switching of the lens barrel  50  between retracted and extended positions begins with the user pushing the grip  222  of the actuator  220 . This moves the actuator  220  out of the primary position and toward the secondary position. While the actuator  220  moves away from the primary position, the first face  239  of the rib  240  of the actuator  220  pushes against the first stop  278  of the drive unit  272 . This causes the drive unit  272  to pivot through the first range of intermediate orientations toward the middle orientation. This pivoting is opposed by the actuator over-center mechanism  198   a  and the drive over-center mechanism  198   b . Movement of the actuator  220  continues until the middle range of conformations is reached. At this point, the biasing by the actuator over-center mechanism  198   a  changes over to biasing toward the secondary position. This forward biasing by the actuator over-center mechanism  198   a  is opposite in direction from the continuing biasing by the drive over-center mechanism  198   b.    
     When the middle orientation of the drive unit  272  is reached, the drive over-center mechanism  198   b  changes over and biases in a forward direction toward pivoting of the drive unit  272  to the second end orientation. At this point, biasing by both over-center mechanisms  198   a ,  198   b  is in the same direction. The actuator  220  continues to move until the secondary position is reached and the actuator stops moving. The drive unit  272  continues moving forward under the forward biasing of the drive over-center mechanism  198   b . The drive unit  272 , in the illustrated embodiment, moves independently of the actuator  220  after the middle orientation is reached. This results in the first stop  278  of the drive unit  272  moving away from the first face  239  of the rib  240  of the actuator  220 . The biasing of the drive over-center mechanism  198   b  pivots the drive unit  272  through the second range of intermediate orientations to the second end orientation. The actuator  220  remains in the secondary position. During the continued pivoting of the drive unit  272 , the second stop  280  of the drive unit  272  comes around and reaches the second face  241  of the rib  240 . 
     The movement of the lens barrel between positions can be delimited by the stops  278 , 280  or by both the stops  278 , 280  and one or two rests or by only rests or features of the support. In the first two cases, the stops  278 , 280  engage the faces  239 , 241  of the rib  240  in limit positions. In the latter case, the stops  278 , 280  are spaced from the rib  240  in the limit positions. 
     In particular embodiments, the camera  10  has a positioner  62 . The positioner  62  is used to delimit the position of one or more lens elements. If the positioner  62  is used to limit travel of a lens barrel  72 , the positioner  62  is also referred to herein as a travel stop  62   a.    
     Referring now to FIGS. 8-10 and  33 - 35 , a travel stop  62   a  is a ring-shaped one-piece plastic casting that has an opening  284  centered on the optical axis  38 . The travel stop  62   a  has an annular main portion  298  and a skid  286  that extends in an axial direction away from the main portion  288 . The skid  286  and main portion  288  are located radially outward from the opening  284 . The skid  286  is spiraled about the optical axis  38  toward the mount  26 . The skid has one or more ramps  290 . Each ramp  290  defines a separate spiral about the optical axis  38 . 
     The ramps  290  of the skid  286  of the travel stop  62   a  are the front rest  54 , in this embodiment The ramps  290  engage the first contact surface  58  of the lens barrel  50  and delimit the extended position of the lens barrel  50  by blocking further forward movement. (See FIG. 34.) In these embodiments, as earlier described, the lens barrel  50  has a main portion  82  disposed in the central passage  40  and a plurality of track followers  80  protruding outwardly from the main portion  82 . The first contact surface  58  is a part of one of the posts  84  of each of the track followers  70 . Each portion of the first contact surface  58  is relatively small and only contacts a radially aligned segment of the respective ramp  290  in the extended position. The segment is the portion of the ramp in contact with the first contact surface and is thus a small part of the ramp. 
     In the embodiment shown in FIG. 33, the travel stop  62   a  also has one or more abutments  294  extending axially outward from the main portion  288  of the travel stop  62   a . Each abutment  298  is arcuate and extends partway around the main portion  298 . The abutments  294  are spaced from the ramp or ramps  290 . Each abutment  294  has one or more contact surfaces  296  that extend along the optical axis  38 . The contact surfaces  296  each have a major dimension parallel to the optical axis  38 . The number, shape, and spacing of abutments  294  can be varied. For example, in the embodiment shown in FIG. 33, each abutment  294  has a first pair of opposed contact surfaces  296  that face each other at the middle of each abutment and a second pair at the opposed ends of each abutment  294 . 
     In this embodiment, the guide  28  has one or more accessways  297  that extend through the forward rim  44 . The accessways  297  are spaced radially outward from the central passage  40 . Each accessway  297  is shaped like a segment of a ring and is aligned with a respective abutment  294 . The abutments  294  can extend into respective accessways  297 , as shown in FIG. 34, or can be recessed from or extend through respective accessways  297 . It is currently preferred that abutments  294  extend forward along the optical axis  38  and that the main portion  288  of the travel stop  62   a  is rearward of the forward rim  44 . Abutments  294  can, alternatively, extend radially outward relative to the optical axis  38 . The travel stop  62   a  is mounted to the guide  28  adjoining the forward rim  44 . The skid  286  of the travel stop  62   a  is located internal to the guide  28 . The ramps  290  face the mount  26 . In the embodiment shown, the skid  286  has three ramps  290  that are spaced from each other, equally spaced about the optical axis  38 , and equally inclined toward the mount  26 . 
     The travel stop  62   a  shown in FIGS. 33-35, has a forward section  300  and an axially inset rear section  302  of the main portion  298 . The forward section  300  has a rear-facing shoulder  304 . In the assembled lens module  22 , the twist ring  66  is trapped between the forward margin  306  of the mount  26  and the shoulder  304  of the travel stop  62   a . The travel stop  62   a  is trapped between the twist ring  66  and the forward rim  44  of the guide  28 . 
     The travel stop  62   a  is pivotable about the optical axis  38  to a plurality of different orientations of the skid  286  relative to the support  24  and the frame  20 . The pivoting shifts the segments of the ramps that are in contact with the first contact surface along the respective ramps. The positioner  62  is pivoted by pushing against one or more of the contact surfaces  296  of the abutments  294 . A spanner or other tool (not shown) having one or more blades or pins can be inserted into one or more accessways and placed against the contact surfaces  296 . The tool can then be used to push the positioner  62  in one or another direction of rotation about the optical axis  38 . The abutments  294  can also be pushed by hand during camera assembly, prior to placement of the front cover. 
     The pivoting of the travel stop  62   a  alters the relative radial alignment of the skid  286  and the lens barrel  50 . As the travel stop  62   a  is pivoted, the segments of the ramps  290  in contact with the parts of the respective posts  84  move along the respective ramps  290 . This changes the axial location of the first contact surface  58  and the rest of the lens barrel  50 , in the extended position. The travel stop  62   a  is adjusted, during assembly, to correct the lens focus for an individual camera  10 . After adjustment, the travel stop  62   a  can be retained in place by friction between parts, by clamping or other fastening, or by bonding the travel stop  62   a  in place with adhesive or welding or the like. 
     In another embodiment shown in FIGS. 36-37 and  45 , the abutments  294  of the travel stop  62   b  are joined together to form a continuous brim that is external to the forward rim  44  of the guide  28 . The travel stop  62   b  is held in place by an overlap of the forward rim  44  and an inner margin  330  of the traveler  62   b . The travel stop  62   b  is otherwise like those earlier described. 
     A rear travel stop (not shown) can be provided in addition to or in place of the front travel stop  62   a . The rear stop is mounted to the guide  28  opposite the travel stop  62   a  and delimits the location of the lens barrel  50  in the retracted position. The rear travel stop has a skid  286  that faces the forward rim  44  of the guide  28 . The skid  286  and other features are otherwise like those earlier discussed. 
     In particular embodiments a coverglass  310  is used, in place of a tool, to adjust the travel stop  62   a  or other positioner  62 . Referring to FIGS. 33,  36 - 37 , and  45 , the coverglass  310  has a window  312  that is transparent or filtering. The coverglass  310  has a reinforcement band  314  that supports the window  312  and can provide reinforcement against impacts. An adjuster  316  is joined to the reinforcement band  314 . The adjuster  316  has one or more lugs  318  that extend toward the mount  26 . In a particular embodiment, the window  312  is curved and has no optical power. 
     The coverglass  310  is mounted to the forward rim  44  of the guide  28  (see FIG. 33) or is mounted to the travel stop  62   a  (see FIGS. 36-37 and  45 ). The window  312  is aligned with the central passage  40  of the support  24 . The lugs  318  are positioned so as to engage the contact surfaces  296  at the middles of the abutments  294  of the travel stop  62   a . (See FIG. 33) The band  314  engages the outer edges  308  of the abutments  294 . In the embodiment shown in FIG. 33, the lugs  318  extend into the accessway  297 . (See FIGS. 33-34.) The coverglass  310  can be a one-piece plastic casting. 
     The coverglass  310  is, at least initially, pivotable about the optical axis  38  relative to the support  24 . When the coverglass  310  is rotated, the lugs  318  push the travel stop  62   a , pivoting the travel stop  62   a  about the optical axis  38 . 
     Referring now to FIGS. 38-40, in particular embodiments of the invention, a postioner  62   b  is used with a lens that does not travel. In this camera  10 , the lens barrel  50  is replaced by a front lens holder  320 . A front lens  322  is held in the front lens holder  320 . A rear lens  326  is held in a rear lens holder  328 . The position of the front lens holder  320  is adjusted along the optical axis  38 , relative to the rear lens  326 , to provide focus adjustment at a single position along the optical axis  38 . This can be a factory adjustment that remains unchanged after the camera is assembled or can be adjustable by the user. 
     The front lens holder  320  has contact surfaces  324  that are pivoted against the ramps  290  of the skid  286  to relocate the front lens  322  along the optical axis  38 , in the same manner as earlier described for the travel stop  62   a.  The coverglass  310  functions in the same manner as in the previous embodiment The coverglass  310  is mounted to the front cover  16  and can be pivoted about the optical axis  38  with lugs  318  of the coverglass  310  in contact with contact surfaces  296  of abutments  294  of the lens holder  320  to rotate the lens holder  320  about the optical axis  38 . In the embodiments of FIGS. 38-40, the abutments  294  extend out radially relative to the optical axis and are joined together into a continuous ring. 
     The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.