| 摘要 |
There is disclosed herein a method and an apparatus which provide a tactile indication of the occurrence of a particular event, such as during the operation of a photographic camera, to provide an indication to the operator that a proper exposure condition, like proper focus, aperture or shutter speed, has occurred. For example, and as particularly shown and described herein, a photographic camera includes an autofocus sensing system which senses when a focusing device, such as the focusing ring, of the camera lens has been adjusted for proper focus. When this focus event occurs, an electromagnet operates a brake to prevent the lens focusing device from being turned or operated further, at least momentarily, to thereby provide to the camera operator a tactile indication that the proper focus has been achieved. The electromagnet can be associated with the camera body to engage the focusing device of the lens, or it can be in or within the lens assembly. The concepts of the invention also are useful for setting the aperture or shutter speed of a camera in response to the brightness level of the scene being photographed (along with the usual input to the camera system of film sensitivity and shutter speed or aperture). In this latter case, the brake momentarily stops the movement of the aperture or shutter speed adjustment ring. The present invention also is useful for various forms of cameras and the like, such as still, movie, photographic, video, and so forth, as well as photographic enlargers. |
