[SMO] Smooth Motion Optics
SMO (Smooth Motion Optics) is a Sony optical design concept for interchangeable lenses that is specifically aimed at achieving the highest possible image quality and resolution for motion images.
SMO design addresses three main issues that are critical for moviemaking:
- Focus breathing (angle of view instability while focusing) is effectively minimized by a precision internal focus mechanism.
- Small focus shifts that can occur while zooming are eliminated by a special tracking adjustment mechanism.
- Lateral movement of the optical axis while zooming is eliminated by an internal zoom mechanism that keeps the length of the lens constant at all focal lengths.
The level of precision required demands both exacting design and constant monitoring during manufacture, but the benefits for moviemaking with large aperture lenses, particularly on large format sensors, are spectacular and well worth the effort.