Motorized zoom lens
A motorized zoom lens ( English : zoom-by-wire ; also autozoom , power zoom or motorized zoom ) is a zoom lens with electromechanical focal length adjustment . The shifting of the lens groups for the focal length adjustment is not done directly mechanically, but is detected with buttons or incremental encoders, occasionally also by swiping gestures on touch-sensitive displays and adjusted by servo motors. Motorized zoom lenses usually also have an exclusively electromechanical focus setting (also called focus-by-wire).
Motorized zoom lenses are mainly found in very compact cameras in which the filigree lens, which can be retracted in the rest position, does not allow a mechanical zoom ring, but also in very large and heavy lenses. In addition, zoom lenses for video cameras are mostly motorized zoom lenses. Using special adapter mechanisms, some standard lenses can also be used as a motorized zoom for video purposes.
Minolta first introduced motorized zoom lenses to the xi interchangeable lenses. In connection with camera programs, an automatic, subject-appropriate focal length preselection by the camera was possible. For Pentax cameras, hybrid motorized zooms were available in the 1990s, which still allowed direct mechanical adjustment.
Motorized zoom lenses are used when they can demonstrate their advantages over mechanical zoom or when the design of the lens does not allow mechanical zoom.
Motorized zoom lenses are advantageous in the following cases, for example:
- heavy lenses which, as mechanical lenses, would require too much force,
- complex lenses that are comparatively filigree and would not withstand direct mechanical operation,
- complex lenses with many movable lens groups that can only be moved by servo motors on the lens group,
- remotely controllable lenses (e.g. surveillance cameras ),
- soft zoom movements or programmable zoom movements in (professional) video cameras,
- complex lenses that require precise calibrations.