FFT Focus Stuck at Maximum Distance — Must Set Focus Before Engaging Cart Control¶

Target Tracking Resolved All rigs BOTH

Summary¶

When Focus Follows Target (FFT) is enabled and the operator engages Cart Control before physically moving the focus motor, the focus axis locks at its current position (often 1,000,000 cm — effectively infinity). The focus motor does not move even as the rig runs the move. The root cause is that FFT needs to know where the focus axis currently is before it can compute target distances; engaging cart control at maximum range gives it a starting point of "infinity" that it cannot resolve from.

Symptoms¶

Focus Follows Target is active and lens calibration is in place
After enabling Cart Control or entering a Cartesian mode, the focus axis reads an extremely large distance (e.g. 1,000,000 cm)
The focus motor does not move during the move — lens stays at infinity
Correct focus values are stored at all waypoints
Running the move without Cart Control engaged works normally

Root Cause¶

When Cart Control is engaged, Flair initialises the focus axis from its current motor position. If the motor is sitting at its maximum travel (infinity stop) and has not been moved since boot or last zeroing, FFT interprets the starting distance as infinity. Once that starting point is set, FFT cannot pull focus down from there — it treats the current position as the reference and stays locked.

The fix is to ensure the focus axis has been physically moved to a known position before Cart Control is activated, giving FFT a realistic starting distance.

Resolution¶

Step 1 — Move focus before engaging Cart Control¶

Before turning on Cart Control (or entering any Cartesian mode):

Manually drive the focus axis to a mid-range position — for example, 1–2 metres.
Confirm the focus readout in Flair shows a realistic distance (not millions of cm).
Then engage Cart Control.

"Move the focus FIRST, then engage cart control." — Community (confirmed by multiple operators)

Step 2 — Verify lens calibration is applied¶

Confirm that:

A lens is selected in Setups -> Lens Setup and the calibration table is loaded
Focus mode is set to Focus Follows Target (not Independent or Follows Object) in the job's focus / target-tracking controls
The camera mount settings are correctly applied in Setups -> Camera Mount Setup (target distance calculations depend on nodal point offsets)

Step 3 — Check for infinite target distance stored in job¶

If the move was programmed while focus was at infinity, the stored waypoint distances may also be at infinity. Rebuild those waypoints:

Physically position the rig at each waypoint.
Measure or estimate the actual distance to the target.
Type the distance directly into the Target Distance column at each waypoint.
Re-run to confirm focus is tracking correctly.

WhatsApp Excerpts¶

"My focus was not moving at all. Fixed by moving focus before engaging cart control — after that FFT worked correctly." — Community operator (paraphrased from multiple reports)

"FFT needs a starting position. If the motor is at max range when you engage carts, it locks there." — Simon Wakley (paraphrased)