A follow focus is a geared wheel that turns the focus ring of a lens so you can pull focus smoothly. To choose one, check that your lenses have gears or can take a gear ring, that your rig has rod support and that the unit has the feel and markings you need.
Why Use One
Turning a lens ring directly by hand can be jerky, and your fingers may bump the camera. A follow focus gives a larger wheel and a defined path, so you can change focus gradually. A marking disc lets you write down distances, and a hard stop lets you return to exact end points. It is most useful in planned shots with a moving subject or a deliberate change of focus.
Check List for Selection
- Rod system. Follow focus units usually mount on a pair of rods, so confirm the rod diameter and spacing of your rig.
- Lens gears. Cinema lenses often have geared rings. Photo lenses might need a clip-on gear ring, which must fit the diameter of the focus ring.
- Height alignment. The gear on the unit must meet the lens gear. Look for a height adjustment or a range of positions.
- Gear pitch. The tooth size on the unit and the ring must match. Check the maker’s guide.
- Hard stops. Adjustable stops are useful for repeatable pulls.
- Whip or crank. Consider whether a handle or extension arm will help another operator pull focus.
Types in Plain Words
| Type | Feel | Best when |
|---|---|---|
| Basic geared wheel | Direct and simple | One operator, light rig |
| With hard stops and disc | Repeatable | Planned focus changes |
| Clutch or slip type | Protects the lens from forcing | Shared use or large lenses |
| Wireless motor system | Remote control | Gimbal or crane work |
Using It Well
- Practise short pulls between two marked points before a real shot.
- Keep the gear lightly engaged, not binding, so the ring turns freely.
- Do not force the ring past its end stop; check where the lens stops before locking the unit’s hard stops.
- Mark the disc with pencil or tape, and clean it afterwards.
- Consider an extra support for long or heavy lenses.
A Quick Test Before Buying or Using
Mount the unit and turn the wheel through the full travel of the lens. The motion should feel even, with no skipping teeth and no slop when you reverse direction. Check that the unit does not shift on the rods under hand pressure. If you shoot with a marking disc, confirm the ring is easy to write on and wipe clean. A unit that feels loose or gritty on a bench will feel worse under pressure on set.
FAQ
Can I use one with autofocus-only lenses?
Many modern lenses focus electronically, so a mechanical unit may not suit them. Check whether the lens has a physical ring with direct travel.
Is a follow focus needed for stills?
No. It is mainly a video tool, though some macro shooters use one for fine focus steps.
The Short Version
Choose a follow focus that matches your rod system and lens gearing, then add hard stops if repeatable pulls matter. Practise before the real take.