What the thread found

• External gear rings can be attached to lenses that lack built-in focus teeth to enable motor-driven follow focus systems.
• Soft rubber wheels or friction-based systems work as an alternative to gear engagement for cameras where gear teeth cannot be used.
• Rubber bands wrapped around both the lens barrel and motor gear can create sufficient friction to drive focus without mechanical teeth engagement.
• Purpose-built add-on gear rings are available from multiple manufacturers in various sizes to fit different camera lens diameters.
• Some Canon HDV cameras have autofocus sensors positioned where external gears would normally mount, requiring alternative friction-based solutions.
• Rubber friction methods have been used successfully on vintage motion picture cameras before modern gear solutions became standard.

Depends on

• Solutions using rubber friction are considered less elegant and may produce noise compared to gear engagement.
• Cheap plastic add-on gear rings can fail under stress during calibration or use with heavy glass.
• Rubber-based systems may require experimentation to find the right tension and configuration for reliable operation.
• Specific gear size compatibility depends on individual lens barrel diameter.
• No standardized solution appears to exist for all camera and lens combinations requiring friction-based focus drive.

Parts

Follow Focus

Same gear or parts

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