Probe / Macro Lens Flips Because Target Is Behind Nodal Point¶
Summary¶
With probe lenses or extreme macro work, Flair can think the target has passed behind the camera or behind the nodal point. In chat this showed up as cartesian mode flips, wants to flip 180 when going into cartesian, arm wants to flip the pan, or a weird go-to after a lens change.
The recurring solution is to set the probe as a camera mount / tilting lens, enter the tube length from sensor to probe tip, verify target distance and nodal/camera offsets, and use Focus Independent when working inside or beyond 1:1 magnification.
Symptoms¶
- Probe lens or macro lens flips when entering Cartesian mode.
- Move flips 180 when switching into Carts.
- Flair thinks the target is behind the camera.
- Target goes behind the lens or behind the nodal point.
- Focus goes to infinity, extend moves forward, or the rig asks for a strange go-to.
- Recalibrating the lens or changing to Focus Independent fixes the behaviour.
Root Cause¶
For very close macro/probe work, the target distance can cross the lens' 1:1 point. Once inside of 1:1, focus is no longer cleanly described as a normal target distance. Flair can interpret the target as being behind the camera/nodal point, so the kinematic solution tries to flip the camera, pan, or arm to keep looking at that impossible target.
Incorrect lens calibration, wrong front nodal, missing tube length, or measuring the target from the wrong reference point can create the same symptom.
Community Solutions¶
[CONFIRMED] Use camera mount / tilting lens and enter tube length¶
For probe lenses, choose the tilting lens workflow and type the tube length. Ben Myers described the measurement as from the sensor to the tip of the probe. This helps stop Flair placing the target behind the camera.
Confidence: 0.92
[CONFIRMED] Use Focus Independent inside or beyond 1:1¶
When the lens is inside of 1:1, switch away from Focus Follows Target / Focus Follows Object if target distance is driving the flip. Use Focus Independent so focus is stored as motor values rather than a target-distance calculation.
Confidence: 0.86
[LIKELY] Recheck lens calibration, target distance, and nodal offsets¶
If Focus Independent does not resolve it, check the lens setup, measured target distance, camera mount offsets, and whether distance is being measured from the sensor plane, front element, or probe tip.
Confidence: 0.84
[FIELD WORKAROUND] Cheat the pivot point deliberately¶
For a tight shot, operators sometimes adjust tube length or nodal offset to move the effective pivot point to a more useful place. This is a deliberate programming cheat, not a calibration truth. Test at creep speed and watch the 3D viewport.
Confidence: 0.72
WhatsApp Excerpts¶
| Timestamp | User | Evidence |
|---|---|---|
| 2021-12-08 07:54 | Jeremy Andrews | "With macro's and probe lenses ... you could be setting a target very close to the front element ... push your lens nodal point PAST that target ... the camera would want to flip around with no warning." |
| 2024-04-25 23:40 | Timothy Heys Cerchio | "Be aware of the 1:1 ratio point on the lens where the Target will 'push' behind the Nodal Point and the Rig will want to flip over by 180 degrees." |
| 2025-10-16 04:04 | Kenneth | "Trying to calibrate the x-tract probe lens ... cartesian mode and also when I try to run a move it flips." |
| 2025-10-16 04:08 | Chavez.Camera | "You're likely inside of 1:1 ... You should switch to focus independent." |
| 2025-10-16 04:22 | Kenneth | "Still wants to flip 180 when going into cartesian..." |
| 2025-10-16 04:22 | Ben Myers | "Use camera mount and choose tilting lens, then type in the tube length (measure from sensor to tip of the probe)." |
| 2025-10-16 04:27 | Chavez.Camera | "Inside of 1:1 flair understands the target to be behind the camera and wants to do the flip you're describing." |
| 2025-10-16 04:38 | Kenneth | "This solved it!" |
| 2026-02-20 02:43 | Indrek | "DZO Xtract ... if i set target/focus closer than Z offset (46cm) it wants to flip 180." |
| 2026-02-20 03:42 | Timothy Heys Cerchio | "Use Snorkel/Probe (or Tilting in F7) lens setup, rather than Standard Lens. With Nodal point just before tip of lens and measures offset to front of lens." |
| 2026-02-20 03:43 | Simon Wakley | "You have to be focus independent if you're going through or to 1:1." |
| 2026-02-20 03:47 | Timothy Heys Cerchio | "Tilting Lens in Flair 7 actually overcomes the 1:1 'flip' issue." |
| 2026-05-22 20:05 | Navid Tansaz | "If you are too close to something and your calibration is off the arm wants to flip the pan ! thinking that the target is behind the nodal point." |
| 2026-05-22 20:07 | Navid Tansaz | "Quick fix is to go to focus independent and change your target distance slightly." |
| 2026-05-22 20:07 | Julio Oliveira | "Recalibrating lenses worked!!" |
Related Issues¶
- See also: Probe / Macro Lens Setup Roundup - Problems and Solutions
- See also: Probe Lens Camera Mount / Tilting Lens - Tube Length, End Angle, and Offsets
- See also: Probe Lens Focus Calibration - Marks, Lookup Table, and Real Distances
- See also: Probe Lens Repeated Go-To Entering Carts - Switch Lens Moves Off
- See also: Focus Follows Object vs Focus Follows Target - Behavioural Differences
- See also: FFT Focus Stuck at Maximum Distance - Must Set Focus Before Engaging Cart Control
- See also: Focus Drifts to Infinity When Switching from Pan/Tilt Tracking to Target Tracking