Abstract:
A tilt shift lens adapter having an adapter body with first and second body portions configured to provide precision tilting and shifting functions is disclosed. Opposite sides of the adapter body are configured to respectively engage a camera and a lens. Tilting and shifting are precisely controlled using precision tilting and shifting mechanisms. The tilting mechanism includes a neutral setting for ensuring precise parallelism between the lens and camera flanges when required. The adapter includes a mount to provide good balance and holding strength when heavy lenses are attached. An optional aperture adjustment mechanism manually adjusts lenses having no aperture ring.

Description:
CLAIM OF PRIORITY 
     This Application claims the benefit of priority under 35 USC §119(e) of U.S. Provisional Patent Application Ser. No. 61/383,759, entitled “Tilt shift lens adapter,” filed on Sep. 17, 2011, and which is incorporated by reference herein. 
    
    
     FIELD 
     The present disclosure relates to lens-to-camera mount adapters, and more specifically relates to adapters that offer both tilting and shifting functions. 
     BACKGROUND ART 
     Lens-to-camera mount adapters are used to attach a lens having a relatively large flange distance to a camera having a shorter flange distance. Adding a tilt function to such an adapter will allow a photographer to adjust the plane of focus to meet the Scheimpflug condition in order to increase depth of field, or alternately to intentionally violate the Scheimpflug condition in order to reduce the depth of field. Adding a shift function to a lens adapter will permit, among other things, the sensor plane to remain parallel to a wall or building while still taking in the full height of the subject. This will allow vertical lines in the object to be perfectly vertical in the image. 
     In order to take full advantage of tilting and shifting capability, the lens should have an image circle that is substantially larger in diameter than the actual image diagonal. So, for example, if a four-thirds format camera is used that has an image diagonal of 21.6 mm, it will be necessary to use a lens designed for a larger format, such as the DX format (28.8 mm image circle) or FX format (43.2 mm image circle). 
     It is also important that the flange distance (i.e. the distance from the lens mounting flange to the image surface) of the lens is substantially larger than the flange distance of the camera. The space between the two flanges will be filled with the lens-to-camera mount adapter, and the space needs to be adequately large to incorporate both tilting and shifting mechanisms. 
     Recently, cameras having a very short flange distance while also having a fairly large sensor (either four-thirds or DX) have become very popular. These are sometimes called “mirrorless” cameras because they use an electronic viewfinder rather than a single lens reflex viewing system. Elimination of the SLR type viewfinding system is what permits these cameras to have such a short flange distance. Examples of mirrorless cameras include the Sony NEX series of cameras, the Olympus series of Micro Four Thirds cameras, the Panasonic series of Micro Four Thirds cameras, and the Samsung NX series of cameras. 
     Many lens-to-camera mount adapters have been developed specifically for mirrorless cameras, ranging from simple adapters in which the camera and lens mounts are rigidly fixed with respect to each other, to adapters that permit either tilting or shifting. Currently there are no such adapters that permit both tilting and shifting. 
     One common problem with mirrorless cameras is that they are too small to provide a tripod mount that is sufficiently robust to support the camera when a large lens is attached. A lens-to-camera mount adapter is an ideal place to locate a robust tripod mount because the mounting location is closer to the center of gravity of the camera-plus-lens system. Also, the size and shape of a tripod mount located on a lens-to-camera mount adapter is not limited by the size and shape of the camera body. This means that the mount adapter can incorporate a quick-release tripod foot compatible with standard tripod heads such as Arca Swiss or Manfrotto. Currently, however, there are no such lens-to-camera mount adapters providing a robust tripod mount. 
     Many current lenses that would otherwise be ideal for mounting to mirrorless cameras via an adapter lack manual control of the iris diaphram. An excellent example are the “G” type lenses manufactured by Nikon. These lenses have no aperture ring. However, Nikon G lenses do have a mechanical aperture linkage in the mounting flange that can be controlled by a properly designed lens-to-camera mount adapter. Currently there are a variety of lens-to-camera mount adapters that provide manual control of lenses lacking manual iris control, but none of these adapters also provide both tilting and shifting functions. 
     SUMMARY 
     In view of the above, there is a need for a lens-to-camera mount adapter with both tilting and shifting functions. In addition, there is a need for such an adapter in which the tilt and shift functions are precisely controlled by means of lead screws or the like. In addition, there is a need for such an adapter to have a means for direct attachment to a tripod or similar support. There is also additionally a need for such an adapter to have a means for manually controlling the aperture for certain attached lenses which lack a manual aperture control means such as an aperture ring. 
     The present disclosure is thus directed to a lens-to-camera mount adapter that permits both tilting and shifting of the lens relative to the camera body. More specifically, the disclosure is directed to a tilt/shift adapter (“tilt shift adapter”) suitable for use with short-flange-distance mirrorless cameras coupled with conventional long-working distance lenses designed for SLR type cameras. The tilting and shifting functions of the adapter disclosed herein are actuated by precision tiling and shifting mechanisms. In an example embodiment, a tripod mount is built-in to the adapter both to achieve better balance when a large lens is attached and also to avoid relying on the camera&#39;s tripod mount, which may not be sufficiently strong. The adapter also optionally includes a manual aperture lever to engage and control the iris mechanism of lenses that lack an aperture ring, such as the aforementioned Nikkor G-type lenses by Nikon. 
     Accordingly, an aspect of the disclosure includes a tilt shift adapter for attaching a lens to a camera. The adapter has an adapter body having an aperture and a first body portion with a first side configured to attach the camera and second body portion with a second side configured to attach the lens. The first and second body portions can move relative to one another to create a tilt and a shift relative to the first and second sides. A a precision shifting mechanism is operably configured to control and set an amount of said shift while a precision tilting mechanism operably configured to control and set an amount of said tilt. 
     Another aspect of the disclosure is a tilt shift adapter for attaching a lens to a camera. The adapter includes an adapter body with an aperture and having a first portion with a first side configured to operatively engage the camera and a second portion with a second side configured to operatively engage the lens. The first and second adapter body portions are configured to be shiftable and tiltable relative to one another via respective shifting and tilting mechanisms operatively arranged with the adapter body portions. The adapter also includes a mount configured to attach the adapter body to an adapter body support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevated view of an example embodiment of an assembly formed by the tilt shift adapter, the lens and the camera, with both lens and camera attached in the landscape position. 
         FIG. 2A  through  FIG. 2C  are respective front, side and rear views showing an embodiment of the tilt shift adapter assembly, with both lens and camera attached in the portrait position. 
         FIG. 3  is a front elevated view showing an embodiment of the tilt shift assembly with both lens and camera attached to the tilt shift adapter in the landscape position, with several functions labeled. 
         FIG. 4  is a side elevation view of the tilt shift assembly with both the lens and the camera attached to the tilt shift adapter in the landscape position, with additional functions and features labeled. 
         FIG. 5  is a drawing showing a top view of an embodiment of the present disclosure with both lens and camera attached in the landscape position with the tilt adjustment all the way in one direction, with several functions and features labeled. 
         FIG. 6  is a bottom elevated view showing the camera side of tilt shift adapter and illustration various functions and controls related to adapter rotation. 
         FIG. 7  is a face-on camera-side view of an embodiment of the tilt shift adapter showing additional functions and controls related to adapter rotation. 
         FIG. 8  is a cross-sectional view of an embodiment of the tilt shift adapter showing details of various mechanisms. 
         FIG. 9  is a face-on lens-side view of an embodiment of the tilt shift adapter several functions and controls related to lens aperture control. 
         FIG. 10  is a side view of an embodiment of the tilt shift adapter showing index markings for the shifting mechanism. 
         FIG. 11  is a cross-sectional, close-up view of the tilt shift adapter showing details related to the tilt mechanism. 
         FIG. 12  is a close-up elevation view of an embodiment of the tilt shift adapter showing details related to the neutral setting of the tilting mechanism. 
         FIG. 13  is a face-on lens-side view of an embodiment of the tilt shift adapter illustrating the neutral position for both tilt and shift. 
         FIG. 14  is side elevation view of an embodiment of the tilt shift adapter showing the aperture indicator markings. 
         FIG. 15  is a close-up cross-sectional view of an embodiment of the tilt shift adapter showing details for a variety of mechanisms. 
         FIG. 16  shows an embodiment of the tilt shift adapter attached to an adapter body support. 
         FIG. 17  is a schematic side view of a camera body with lens flange, lens mounting pin, and image plane. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to lens-to-camera mount adapters that permit both tilting and shifting, and more specifically is directed to such adapters suitable for use with short flange distance mirrorless cameras coupled with conventional long-working distance lenses designed for SLR type cameras. The lens-to camera mount adapter disclosed herein is referred to as a “tilt shift adapter” or just “adapter” for short. The combination of a tilt shift adapter and at least one of a lens and a camera is called an “assembly” and is identified by reference number  4 . 
     With reference to  FIGS. 1 ,  7 ,  10  and  13 , an exemplary adapter  10  is shown as part of an assembly  4 . Adapter  10  includes a first body portion  11  with a first side  11 A configured to operably engage a camera  300  and a second body portion  12  with a second side  12 A configured to operably engage a lens  200 . An aperture  16  in body portions  11  and  12  allows the passage of light from lens  200  attached to the second side  12 A to camera  300  attached to the first side  11 A. An example adapter  10  has a rounded top  13  with generally parallel edges  22  when viewed face on. 
     First and second body portions are engaged so that they can move relatively to one another to create a tilt and a shift relative to first side  11 A and second side  12  (i.e., between the first and second sides). As described below, the amount of tilting and the amount of shifting can be precisely controlled by tilt adjustment screws  109  and shift adjustment screws  108 . 
     Example first and second sides  11 A and  12 A are respectively configured with standard camera-engaging and lens-engaging devices  124  and  115  respectively, as is used in the art. An exemplary engagement device is a bayonet mount. Threads can also be used. The exact size and shape of the aperture  16  depends on the requirements and specifications of the engagement devices  124  and  115 , respectively. 
     The first and second sides  11 A and  12 A include respective first and second flanges  124  and  115  that respectively engage camera and lens flanges of camera  300  and lens  200  being operably coupled to the adapter. The first and second flanges  124  and  115  are also called the camera flange and the lens flange, respectively. The first and second flanges  124  and  115  can be tilted and shifted with respect to one another by tilting and shifting the first and second body portions  11  and  12 , respectively. 
     The tilting and shifting motions are constrained by cylindrical and planar dovetail bearings  117  and  110 . In both cases, play in the dovetail bearings  117  and  110  is eliminated by tilt movement adjustment screws  109  and shift movement adjustment screws  108 , respectively. Adjustment screws  108  and  109  are tipped with slide adjustment bearing material  145  to provide a smooth sliding friction. 
     The tilt and shift dovetail bearings  117  and  110  are independent from each other, meaning that the tilting and shifting motions can be carried out either separately or in combination. Both the tilt and shift motions are precisely controlled by the aforementioned precision tilting and shifting mechanisms that include in an example corresponding leadscrews  131  and  126 , respectively, tipped with ergonomic knobs  105  and  106 , respectively. The precision tilting and shifting mechanisms can be used to precisely set select amounts of tilt and shift. 
     The adapter  10  includes an extended body portion  14 . The extended body portion  14  includes a side  14 A that accommodates a spring-tensioned lock lever  118  ( FIG. 6 ), whose function is explained below. The extended body portion  14  includes a bottom edge  15  to which is attached a mount  101 , e.g., a mounting plate, that allows the adapter  10  to be mounted to an adapter body support  400 , i.e., a support structure, such as a tripod (see  FIG. 16 ). While mount  101  is sometimes referred to below as a “tripod mount,” it is not limited to mounting to tripods. Mount  101  is shown attached to the bottom edge  15  of the extended body portion  14  using screws  149 , by way of example. 
     In addition to tilt and shift motions, the adapter  10  features a rotation function so that the tilting and shifting can take place in different directions. This is accomplished by a precision rotation bearing  150  that lies between the first body portion  11  and the first flange  124 . As mentioned above, the first flange  124  is configured to couple the adapter  10  to the camera  300 , and so it remains fixed relative to the camera. By rotating the first flange  124  relative to the remainder of the adapter  10 , the adapter is able to rotate relative to the camera  300 . This allows the shifting and tilting motions to take place along either the landscape or portrait direction of the camera  300 , or along at least one and preferably several intermediate angular positions. 
     In an example, the rotation is controlled by the aforementioned spring-tensioned lock lever  118  shown in  FIG. 6 . Rotation is locked by engaging the hooked end  119  of lock lever  118  with any of several corresponding holes  151  located along the outer edge of the first flange  124 . In an example, the spacing of holes  151  permits angular rotation from zero to 90 degrees in angular increments, such as 30-degree increments. 
     In an embodiment, the adapter  10  has a maximum shift of +/−8 mm, a maximum tilt of +/−8 degrees, and a maximum rotation of 90 degrees to permit both portrait and landscape camera orientations. The adapter  10  includes bayonet rings  115  and  124  for attaching a lens  200  and a camera body  300 , respectively. The tripod mount  101  is interchangeable to permit use with an arbitrary variety of tripod heads. 
       FIGS. 2A through 2C  shows three elevation views (front, side and rear, respectively) of assembly  4  with camera and lens attached to tilt shift adapter  10  in the portrait orientation. 
       FIG. 3  shows a tilt drive knob  105  and a shift drive knob  106  that control the tilt and shift motions respectively. The aperture setting indicator  107  and shift scale  104  provide a visual indicator for the aperture value and degree of shift, respectively. The lens unlock button  107  is pressed to release the lens  200  to allow its removal. The camera-mounted lens unlock button  301  is normally used to release lenses attached to the camera  300 , but in the present case it is used to release adapter  10 . 
     In  FIG. 4 , adjustment screws  108  are used to eliminate play in the shifting mechanism. The aperture set knob  112  is moved in a short arc to manually adjust the aperture of suitable lenses  200 . This is particularly useful for Nikkor G type lenses (manufactured by Nikon Corporation), which have a mechanical iris control tab but lack an aperture control ring. 
     In  FIG. 5 , the adapter  10  is shown in a maximum tilt configuration. The adjustment screws  109  are used to eliminate play in the tilting mechanism. The center of rotation of the tilt motion approximately coincides with the image plane. This ensures that there is little or no focus shift in the center of the image when the lens is tilted. 
       FIG. 6  illustrates features related to adapter rotation. This rotation is used to rotate the adapter  10  relative to the camera flange  124  of camera  300  so that the camera orientation can be switched from landscape to portrait orientation or vice versa. The spring-tensioned lock lever  118  allows controlled adapter rotation by engaging the camera flange  124  at holes  151  spaced at fixed angular increments my means of a hook  119 .  FIG. 6  also illustrates the screws  149  that are used to attach mount  101  to extended body portion  14 . 
       FIG. 7  illustrates additional features related to adapter rotation. In  FIG. 7 , the camera&#39;s lens locking pin  302 , which is analgous to the lens locking pin  116  on the adapter, engages with the hole  125  in the camera flange  124  to allow precise adapter rotation while keeping the bayonet ring rigidly fixed to the camera. The oblong slot  122  in the spring-tensioned lock lever  118  allows the lever to rotate about the bearing  121  while the bearing screw  123  prevents the lever from lifting up out of its plane of rotation. The spring-tensioned lock lever  118  is actuated by grasping the lock lever knob  120  and moving it to-and-fro. 
       FIG. 8  is a cross-sectional view of the adapter that illustrates several mechanisms and features of an embodiment of the present invention including the aperture drive ring  111 , the aperture drive knob  112 , the shift drive knob  106 , the shift movment lead screw  126 , the shift movement drive nut  127 , and dovetail tilt  117  and shift  110  guides. 
       FIG. 9  is an elevation view of side  12 A shown when the lens flange  115  is shifted to its maximum vertical position. Several mechanisms and features are illustrated, including an aperture indicator  113 , a lens locking pin  116 , a lens locking pin retractor button  107 , the shift drive knob  106 , the tilt drive knob  105 , a portion of the dovetail shift gude  110 , the aperture drive ring  111 , the aperture drive knob  112 , and the lens engagement hook of the aperture drive,  114 . 
       FIG. 10  is a side view showing the shift indicator line  128 , the shift index scale  104 , the first body portion  11 , the first side  11 A, the second body portion  12 , the second side  12 A, the first flange  124 , the second flange  115 , the lens locking pin  116 , the tilt drive knob  105 , the shift drive knob  106 , the extended body portion  14 , the side  14 A that accommodates a spring-tensioned lock lever  118  with lock lever knob  120 , and the bottom edge  15  of the extended body portion to which mount  101  is attached. 
       FIG. 11  is a cross-sectional view of the adapter  10  that illustrates several mechanisms, including the tilt drive lead screw  131 , the self-aligning tilt drive lead screw bearing  132 , the self-aligning tilt drive nut  133 , the rotation bearing for the self aligning tilt drive nut  134 , the lens lock pin sleeve  135 , the bottom of the spring-loaded lens locking pin  136 , the lens locking pin  116 , the lens locking pin lever  130 , the shift drive lead screw  126 , the shift drive nut,  127 , the cylindrical dovetail tilt guide  117 , the linear dovetail shift guide  110 , the first side flange (i.e., camera flange)  124 , and the second side flange (i.e. lens flange)  115 . 
       FIG. 12  is a detail view of the second side showing details related to the neutral setting of the tilt mechanism. This mechanism is important because it provides a precise and repeatable means for making the second flange  115  parallel to the first flange  124 . This setting will be used very often in photography when no tilt adjustment is desired. The tilt scale  137  reads an angle (e.g., one degree) for each tic mark. The vernier index line  138  for the tilt scale permits tilt readings to within a finer angle, such as 0.5 degrees. A tilt lead screw bearing cover  140  also serves as a zero position stop for a zero tilt lever  139 . An eccentric sleeve bearing  149  is shown for the zero tilt lever  139 . A countersunk sleeve bearing lock  142  is also shown. A zero tilt lever engagement stop  143  is used to position the zero tilt lever  139  in the proper position in order to engage the zero tilt lever stop  140 . 
       FIG. 13  is a view of the second side of the adapter  10  when set in a neutral position for both tilt and shift (i.e., zero tilt and zero shift).  FIG. 13  shows the rounded top  13 , parallel edges  22 , extended body portion  14 , bottom edge  15  of the extended body portion, along with mount  101 . 
       FIG. 14  illustrates the aperture open indicator  103  and closed indicator  102 . The small central dot symbol  102  indicates the minimum aperture position, and the large central dot symbol  103  indicates the maximum aperture position. Indicator lines  153  show intermediate aperture values. 
       FIG. 15  illustrates a variety of additional mechanisms and features, including the lens locking pin  116 , one of several lens bayonet springs  144  that provide a snug fit of the lens onto the second side flange  115 , the slide adjustment bearing material  145  which provides a smooth sliding friction, one of the tilt movement adjustment screws  109 , the compression spring  146  for adapter rotation, one of several set screws  147  to lock the inner ring of the adapter to the camera flange  124 , the portion of the adapter body  148  that rotates relative to the camera flange when the adapter is rotated from landscape to portrait orientation (or vice versa), and the rotation bearing surface  150 . 
       FIG. 16  illustrates an adapter  10  according to the present invention attached to an adapter body support  400 . In this figure the body support  400  is shown as a tripod, but in practice other types of supports may be used, such as a rigid pier, a clamp mounted to a pole, a beanbag support, or any other camera supporting means known in the art. 
       FIG. 17  is a schematic drawing of a camera  300 , including the camera body  305 , lens flange  303 , lens mounting pin  302 , and image plane  304 . 
     Thus, embodiments include a lens-to-camera mount adapter, referred to herein as a tilt shift adapter (or just “adapter”), with both tilting and shifting functions. In addition, the adapter has tilt and shift functions that are precisely controlled, e.g., by means of lead screws or the like. In addition, example adapters include means for direct attachment to a tripod or similar support. Example adapters also have means for manually controlling the aperture for certain attached lenses which lack a manual aperture control means, such as an aperture ring. 
     The example embodiments described above is suitable to adapt Nikon F-mount lenses onto Panasonic or Olympus Micro Four Thirds camera bodies. Since the flange distance DF (i.e., the distance from the lens mounting flange  303  on the camera body  305  to the camera image plane  304 ; see  FIG. 17 ) of Micro Four Thirds cameras is 19.25 mm and the flange distance for Nikon F-mount lenses is 46.5 mm, the distance between the flange surfaces  115  and  124  of an embodiment is 27.25 mm. In addition, the example embodiment can provide manual aperture adjustment for Nikon “G” type lenses having an F-mount. 
     Many other embodiments fall within the scope of this disclosure. For example, in order to be compatible with Sony NEX series cameras having a flange distance (see  FIG. 17 ) of 18 mm, the distance between the flange surfaces  115  and  124  would have to be increased by 1.25 mm relative to an adapter designed for Micro Four Thirds cameras. The adapter  10  may also be made compatible with lenses mounts other than the Nikon F-mount standard. Such lens mounts include but are not limited to Canon EOS, Sony Alpha, Pentax K, Olympus OM, Minolta Maxxum, M42, Yashica/Contax, and Leica R. Exemplary embodiments incorporating various different tripod adapters to fit different tripod heads are also fall within the scope of this disclosure. Such tripod heads include but are not limited to those manufactured by Arca-Swiss, Manfrotto, and Gitzo. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.