The present invention generally relates to the field of stabilized equipment supports, and more particularly, to an apparatus for supporting light-weight cameras or other equipment which may be orientation- and/or stability-sensitive so that such equipment is isolated from such unwanted motions.
So-called "hand-held" cameras have been in existence virtually since the beginning of photography. Whether for still pictures or for motion pictures, by virtue of the artistic needs of such media, every model of camera which was light enough to be lifted has at some time been "held" by a human operator. The inherent instability of such equipment immediately becomes a corresponding factor.
For example, in connection with still photography, slow emulsions or reduced lighting often tends to require relatively long exposure times for the films being used. Any motion of the camera, particularly angular motion, therefore tends to produce a blurring of the image. However, it is axiomatic that the human operator is constantly subject to some degree of uncontrollable motion. What is more, these motions tend to increase and are even less controlled if the salient parts of the operator's anatomy are operating under load, through an exerted force. This, of course, applies to the hands and arms of an operator which are holding and/or supporting such camera equipment. These problems are multiplied when motion pictures are involved, since the operator may now need to walk and at times even run with the camera to obtain the necessary images.
By virtue of their construction, cameras are compact, relatively dense objects, with relatively little rotational inertia. What is more, such cameras traditionally have a center of gravity which is located within the camera, at a position which is inaccessible to the operator. As a result, holding such a mass by its outer surfaces means that most motions of the operator will tend to exert considerable leverage in directions effectively tangential to the camera's center of gravity, and will therefore result in an angular motion of the camera, around the axis which passes through the camera's lens. This kind of motion (whether in "pan", "tilt" and/or "roll") is quite disturbing to both still photography and motion picture photography. While it is true that within the limits of human strength, the operator's hands and arms can often dampen out such spatial motions (up/down, side-to-side, in/out), it is again axiomatic that they cannot simultaneously apply the delicate "touch" (contact) which is generally needed to effectively orient the camera in the course of its operation.
The history of photography is replete with attempts to solve these problems. One rather early approach to this may be found in U.S. Pat. No. 2,007,215 (Remey), which teaches a counterbalanced and isolated support for a portable motion picture camera which generally takes the form a needle extending from a handle for the camera, received in a cup associated with the camera's body. This "needle-in-cup" configuration served to provide a degree of isolation between the camera and the operator, but suffered from a variety of disadvantages. For example, the disclosed arrangement lacked an effective means of orientation, and employed burdensome counterweights, combining to require the unit to be held at an awkward distance from the operator's body. What is more, the unit could not be panned relative to the operator, and was difficult to trim into balance.
Still other approaches to the problem involved devices having gyro-controlled prisms and/or mirrors that could operate to alter the optical path for the light entering the lens of the camera in order to compensate for vibrations of the unit. While these devices were somewhat effective for certain high-frequency vibrations, they were relatively ineffective for motions along the roll axis (around the axis passing through the lens). What is more, they added weight to the overall unit and tended to introduce motions of their own if their operational limits (parameters) were overstepped.
Yet another approach to camera stabilization involved the use of various camera pods, shoulder mounts and braces which were developed in an attempt to secure the camera's mounting (position) to the operator's body, so that only the motions of the body's trunk would effect the shot then in progress. However, the resulting motions were only somewhat reduced since such measures tended to produce motions of a slightly longer period, and therefore proved to be only partly effective since constant movement remained an ever present factor in connection with a human operator. Thus, unacceptable angular motion nevertheless tended to prevail, even when the operator was standing still, and became even more of a factor when the operator attempted to walk or run with the unit.
It was in this environment that the devices described in my U.S. Pat. No. Re. 32,213 (Brown), and later U.S. Pat. No. 4,208,028 (Brown et al) were developed. The devices described in these patents generally approach the problem of camera stabilization by providing a spring-loaded equipoising arm for supporting a gimbal-mounted expanded camera system. The disclosed unit serves to isolate the camera from both angular and spatial motions and has proved to be quite effective in allowing the camera operator to produce exceedingly stable images in a variety of different situations. Indeed, the unit serves to allow an ambulatory camera operator to produce a moving shot equivalent to those previously made by camera "dollies" running on a track, the previously recognized method for capturing such sequences. As a consequence of this, such devices have become standard tools in the motion picture and video industries, operating to satisfy a variety of divergent needs in such industries.
However, such devices were primarily designed to support relatively large film and video cameras, exhibiting significant weights. Even the lightest of cameras contemplated for use in connection with such systems were on the order of 20 pounds, and it is presently not uncommon for complete systems (including the stabilized mounting, camera, and supporting equipment) to exceed 90 pounds as operating requirements become more varied and complex. Interestingly, it was discovered that as the weight of the unit increased, the stability of the resulting image also tended to increase (presumably resulting from the use of a more inert unit). It was therefore believed that the lighter the camera, the less useful would be such a stabilization device.
Indeed, special steps were taken in U.S. Pat. No. 4,474,439 (Brown) to develop a more sophisticated version of the expanded, gimbal-supported camera system having a configuration which was adjustable to respond to the various operational requirements of the ever-increasingly sophisticated uses for such equipment. Nevertheless, the total weight of the resulting unit was approximately 17 pounds (without the camera), and it was found that even this light-weight unit could not be used to effectively support a camera lighter than itself.
It was at this point in time that another aspect of camera technology evolved: the portable (consumer-operated) video camera. A variety of formats for this product were initially developed, with continued efforts towards miniaturization and simplification due to the unit's consumer-oriented market. Initial attempts at developing an independent, fully self-sufficient consumer video camera (i.e., "CamCorder") involved the so-called "full-sized" CamCorders, self-contained camera and recording units designed to fit on the shoulder of the operator, with a viewfinder mounted forward and to the side of the resulting unit. These "full-sized" CamCorders tend to weigh an average of 5.5 pounds in their more recent implementations. From this there followed the development of the so-called "compact" CamCorders, which are rapidly capturing a significant portion of the consumer market. These "compact" CamCorders generally operate either in the VHS-C or 8 mm video formats, and are comprised of self-contained camera and recording units which are generally on the order of 2.6 pounds in weight. Due to their small size, such cameras are generally supported entirely by the hand (or hands) of the operator, rather than being placed over the operator's shoulder, being held in front of the face with the viewfinder (generally top-mounted) in close contact with the operator's eye.
By virtue of their appeal to the general consumer, a large number of video "CamCorders" have been sold. Each of these units is of course subject to the instability inherent in larger, commercial units. However, in addition to the traditional instability of a hand-held camera, these units are being operated by amateur photographers, still further complicating matters. This is particularly so in connection with the relatively small "compact" CamCorders, which are entirely hand-held, as distinguished from the "full-sized" CamCorders which at least benefit from the support of the operator's shoulder. In any event, the common result is an unstable and often unacceptable video image. This is particularly so when the operator departs from a stationary position, and attempts ambulatory operation of the unit. The unfortunate result of this is a video camera which, by virtue of its size, is particularly portable, but which is unable to achieve its full potential because of its inherent instability.
Thus, the ultimate goal is for the amateur operator to be able to use the full potential of the portable video cameras which have recently been developed, to follow his children, to walk with friends, or to amble through interesting locales, while producing images that are smooth and free of the degradation in apparent resolution which is caused by vibration of the unit, and of the troublesome effects of slower, low frequency oscillations. Improvements to the video cameras themselves have aided in achieving this goal. For example, most of these video cameras now routinely operate at extremely low light levels (often less than 5 lux), and incorporate devices that automatically control focus, iris and color balance. Resulting from such simplification, most of the problems faced by the professional motion picture producer are essentially absent from these consumer oriented counterparts, inherently facilitating the camera operator's task. In essence, the only major problem which remained to be solved involved the stability of the camera in the course of these operations.
Efforts have been made to respond to this problem, primarily by providing miniature versions of many of the traditional camera supports which have been used in connection with the larger, commercial camera equipment used by the professional. Miniaturized shoulder mounts, braces and monopods, and even variations on the optically stabilized approach which operate to orient the lens and video receptor (CCD chip), have been attempted. However, these devices have failed to do any more than alleviate the problem of instability, and all tend to perpetuate the respective peculiarities and problems associated with their full-sized counterparts.
This trend toward the miniaturization of camera stabilizing equipment led me to consider a miniaturization of the camera support disclosed in my earlier U.S. Pat. Nos. Re. 32,213; 4,208,028; and 4,474,439. However, this too proved to be less than satisfactory in implementation.
First, there is the impracticality of such an approach. The average weight of a consumer video camera (between 3 and 6 pounds) can generally be adequately supported by an operator for a reasonable duration. Of course, this will vary according to the strength of the operator and the duration of the "shooting period". However, since the average operator is well able to adequately support the camera for an acceptable (and useful) period of time, it is unlikely that all but the most ardent user of the apparatus would find the need, or even be willing to pay for or indeed wear the elaborate equipoising arm and suit of such a system.
Second, as previously indicated, video cameras weighing 3 to 6 pounds tend to develop an insufficient counterbalancing weight, and are therefore inappropriately combined with even the smallest available version of such equipment. Further reducing the size of such equipment would only tend to produce a device which is nevertheless cumbersome, and noticeably less stable than the professional version of the unit because of the insufficient inertia which would be available to oppose the forces applied to the unit by the operator. In essence, this can be summarized by considering that while it would be possible to reduce the size of the support apparatus, it is impossible to correspondingly reduce the size of the operator's hands, resulting in excessive forces being applied to the "orienting" portions of the floating camera support.
Another simplification of such an apparatus which has been attempted by another practitioner in the art is to delete the equipoising arm in favor of a handle attached directly to the gimbal yoke of the camera support described, for example, in U.S. Pat. No. 4,474,439. However, this generally results in less stability for the overall unit than was originally intended, and still requires two hands for operation of the unit in a non-ergonomic offset position which tends to cause undue strain on the user's wrists and inordinate forces on the extended arm of the user. This is still further complicated by the significant size and excessive weight of the resulting unit, so that the ultimate results achievable by such a unit would by and large be considered unacceptable.
Thus, these various approaches failed to provide an apparatus which was fully and satisfactorily operative in effectively eliminating the problems of instability encountered in connection with operation of the ever-improving portable camera equipment which has been developed, and it therefore remained to develop a stabilized equipment support which was particularly well suited to the special requirements of light-weight, hand-held camera equipment, particularly consumer-oriented video cameras and the like.
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USPTO Backgrounds