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Lens Moves Flag Causes Unwanted Camera Gotos in Carts Mode

CONFIRMED BOTH

Summary

With the Lens Moves flag turned ON after lens calibration, Flair compensates for nodal point movement during focus pulls. In Carts modes, this compensation can produce small unexpected camera gotos — sometimes large enough to trip the rig. Fix: turn OFF the Lens Moves flag after calibration is complete.

Symptoms

  • Camera makes a small unexpected goto during a move, particularly in Carts mode
  • Rig trips on an axis that should not have moved
  • Behaviour occurs after lens calibration with the Lens Moves flag enabled
  • The goto is small but unpredictable

Systems Affected

BOTH
  • Flair Classic and Flair 7
  • Any rig using Carts mode (typically Milo, Modula, and other carts-based systems)
  • Occurs whenever the Lens Moves flag is left ON after lens calibration

Cause

The Lens Moves flag in Flair enables compensation for the nodal point shifting as the lens is focused. When you rack focus, the physical nodal point of the lens moves, which would cause an apparent camera position shift in Carts mode. With Lens Moves ON, Flair calculates this shift and moves the camera axes to compensate.

If this flag is left ON after calibration is complete, the compensation continues to run during normal moves. This produces small, unexpected camera axis movements — gotos — every time the focus axis changes position. In Carts mode, even a small unexpected camera position change can exceed a soft or hard limit, tripping the axis.

"Sometime the camera wants an odd small goto off from the expected position. I am investigating this but it MIGHT be due to the calculated motion of the nodal point when you focus. To fix this turn the 'Lens Moves' Flag off AFTER you have calibrated the lens. In cart control this small goto might even cause the rig to trip." — Simon Wakley, 2022-09-15

Fix

After completing lens calibration, turn OFF the Lens Moves flag.

The flag is only needed during the calibration process itself. Once calibration data has been captured, disable it before operating the rig normally.

Risk of rig trip in Carts mode

If you are in a Carts mode and the rig trips unexpectedly, check whether the Lens Moves flag is enabled. Disable it and clear any trip before resuming.

Source: talk.mrmoco.com — Odd small camera gotos — Post by Simon Wakley, 2022-09-15

Official Documentation

Flair 7 Manual — Ch.6 Lens Calibration: Lens Moves Flag

Flair Classic Manual — Ch.7 Lens Calibration: Nodal Point and Lens Moves

Revision History

Date Change Editor
2026-05-29 Initial extraction from forum topic 1067 Tom D / Claude Code