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Focus Calibration Warning — Invalid Focus Position or Target Distance

CONFIRMED ALL RIGS

Summary

When completing a focus lookup table calibration, Flair may show a Warning dialog:

"Invalid focus position or target distance. Please check that there are no duplicated entries, that the focus positions are positive and increasing, and that the target distances are also positive and decreasing."

This means one or more rows in the lookup table violate Flair's validation rules. The most common cause — especially on Cinebot rigs with Tilta Nucleus-M motors — is the focus motor running in the negative direction, so close focus registers as a negative value instead of a positive one. The fix is to reverse the motor direction before re-calibrating.

Symptoms

  • Warning dialog appears when pressing Complete Calibration in the Flair 7 focus calibration wizard
  • The "Reverse motor detected" indicator may be visible in the calibration dialog
  • During calibration, the mid-point or close-focus point shows an unexpectedly large percentage (e.g. 300–1800%) instead of a sensible value
  • Lookup table entry cannot be saved or accepted
  • Issue is specific to one lens/motor setup — other lenses calibrate normally

The Three Causes

Cause 1 — Focus motor running in the negative direction

Flair requires focus axis values to start at 0.0000 at infinity and increase positively toward close focus. If the Tilta motor's polarity is wrong, close focus will produce a negative value (or a value larger than 1 when it should be smaller than 1). Either way, the lookup table entries are not "positive and increasing" and the validation fails.

Timothy Heys Cerchio (Dec 2024): "The Tilta to Flair relation can be wrong in 2 ways: - Zero value on Close Focus and 1.0000 on Infinity - 0.0000 on Infinity and −1.0000 on Close Focus"

Timothy Heys Cerchio (Mar 2024): "Usually for Focus Axis we would prefer range of motion to be from 0 (infinity) to Positive Max Limit (close focus). In your case you may want to Reverse Motor."

Cause 2 — Duplicate entries in the lookup table

If the same focus position (motor value) is stored more than once — e.g. by accidentally storing twice at the same point — the validation rejects the table. Middle-clicking a row clears it; check for any two rows with identical values in the position column.

Cause 3 — Out-of-order or zero target distances

Target distances in the table must be positive and must decrease as the focus position increases (further focus distance = smaller motor position, closer focus distance = larger motor position). A row left at 0.000 cm or a row where distance increases as motor position increases will also fail.

Fix

[CONFIRMED] Step 1 — Identify the polarity state

  1. In Flair, go to Axis Setup → Focus axis and set the axis type to Independent
  2. Drive the motor to ∞ — note the value (should be 0.0000)
  3. Drive to close focus — the value should be a larger positive number (e.g. 0.9–1.000 for Tilta)
  4. If close focus gives a negative value or a value smaller than infinity: the motor polarity is wrong → proceed to Step 2
  5. If close focus gives a value much larger than 1 (e.g. 3.0, 18.0): the scaling may also be wrong → check Axis Setup min/max limits

[CONFIRMED] Step 2 — Reverse the motor direction

Option A — Reverse in Flair Axis Setup (Cinebot / standard motor)

  1. In Axis Setup → Focus, tick the Reverse Motor checkbox
  2. Save and re-engage the axis
  3. Re-verify: drive to ∞ (should be ~0.0000), drive to close focus (should be positive and increasing)
  4. Redo the focus calibration from scratch

Option B — Physically re-orient the Tilta motor

Vinny (Dec 2024): "This happens for us when our Tilta motor isn't facing outwards — like the screen towards subject."

  1. Loosen the Tilta motor from its mount
  2. Rotate it 180° so the screen faces outward (away from the lens)
  3. Re-attach and re-calibrate

Option C — Drive against a physical limit to flip Tilta polarity

Timothy Heys Cerchio (Dec 2024): "If you are having this problem on the Cinebot with Tilta Motors, you can either turn the motor the other way round or get it to reverse its polarity by driving it against a limit through Flair."

Niko (Dec 2024): "I fixed it calibrating again after reversing direction. By calibrating I mean pressing the physical calibration button."

  1. In Flair, engage the focus axis
  2. Drive the motor deliberately against one of its hard limits until the Tilta motor self-calibrates its direction
  3. Press the physical calibration button on the Tilta motor body if available
  4. Re-check values and redo focus calibration

[CONFIRMED] Step 3 — Clear the lookup table and re-calibrate

Once the motor direction is correct:

  1. Open the focus calibration dialog → switch to Lookup Table mode
  2. Middle-click the top of each used column to clear all existing entries — do not leave rows at 0.000 distance
  3. Re-enter calibration points: start at ∞ (0.000 motor value → your far distance), work toward close focus (increasing motor values → decreasing real distances)
  4. Press Complete Calibration — the warning should no longer appear

The golden rule

Timothy Heys Cerchio: "The best rule to start lens calibration in the right way is Zero (0.0000) on ♾️ and Closest Focus as a positive value (1.000 for Tilta Motors)."

confidence_score: 0.90

WhatsApp Excerpts

[3/12/2024, 8:30:40 am] ~ Luke Campbell: Flair 7 Cinebot question - I've had a couple times when calibrating focus that when I went to go to mid point of lens instead of go to 50% it was showing it at 300-1800% and based on scaling of course would not take. I can't replicate this problem repeatedly but wondering if anyone has seen this behaviour.

[3/12/2024, 8:32:13 am] ~ Vinny: This happens for us when our Tilta motor isn't facing outwards - like the screen towards subject.

[3/12/2024, 8:33:32 am] ~ Ben Myers: Was just about to say that you may need to reverse the focus axis and try calibrating again.

[3/12/2024, 10:04:24 am] Timothy Heys Cerchio: This kind of behaviour in Flair is usually caused by the Focus Motor going in the negative direction. Check the values when set to Focus Independent.

[3/12/2024, 10:05:10 am] Timothy Heys Cerchio: If you are having this problem on the Cinebot with Tilta Motors, you can either turn the motor the other way round (or set it up on the other side of the lens) or get it to reverse its polarity by driving it against a limit through Flair.

[3/12/2024, 10:12:01 am] Timothy Heys Cerchio: The best rule to start lens calibration in the right way is Zero (0.0000) on ♾️ and Closest Focus as a positive value (1.000 for Tilta Motors).

[3/12/2024, 10:22:01 am] Timothy Heys Cerchio: Also the Tilta to Flair relation can be wrong in 2 ways: - Zero value on Close Focus and 1.0000 on Infinity. or - 0.0000 on Infinity and -1.0000 on Close Focus.

[16/3/2024, 5:35:32 am] Timothy Heys Cerchio: Usually for Focus Axis we would prefer range of motion to be from 0 (infinity) to Positive Max Limit (close focus). In your case you may want to Reverse Motor.