> For the complete documentation index, see [llms.txt](https://stage-precision.gitbook.io/grid/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://stage-precision.gitbook.io/grid/camera-calibration/calibration-workflows/lens-and-tracking-calibration-rotation-only.md).

# Lens & Tracking Calibration (Rotation Only)

## Lens & Tracking Calibration (Rotation Only)

**Lens & Tracking Calibration (Rotation Only)** is used when the camera does not freely move through 3D space, but mainly rotates from a fixed or mostly fixed position.

This workflow is similar to **Lens & Tracking Calibration**, but it is optimized for camera systems where the available movement is mostly rotation.

Typical examples include:

* pan/tilt camera systems
* PTZ-style camera systems
* fixed cameras with a rotating head
* cameras mounted on a static tripod or head
* systems where position is fixed, but pan and tilt are tracked

{% hint style="info" %}
This page only describes workflow-specific best practices. The general Calibration Object setup, Capture Window, capture process, and output handling are explained in the **Using the Calibration Object** section.
{% endhint %}

***

## When to Use This Workflow

Use **Lens & Tracking Calibration (Rotation Only)** when the camera has tracked rotation, but no useful tracked position movement.

The camera may still be physically mounted on a tripod, head, bracket, PTZ mount, or other fixed position system.

#### Typical Use Cases

Use this workflow for:

* rotation-only camera tracking
* pan/tilt systems
* PTZ camera workflows
* static camera position with tracked orientation
* camera heads that provide pan and tilt values
* setups where zoom and focus should be calibrated together with the rotation alignment

#### When Not to Use It

Do not use this workflow if the camera can freely move through 3D space and provides full position and rotation tracking.

Use another workflow instead when:

* the camera provides full position and rotation tracking → use **Lens & Tracking Calibration**
* only the lens needs calibration → use **Lens Calibration**
* an existing Lens Profile should only be aligned to tracking → use **Tracking Alignment**
* the camera is static and has no live movement data → use **Simple Static Calibration**
* the setup uses an Axis 2D rail / pole system → use **Axis-Pole Calibration**
* Calibration Screens cannot be used → use **Alignment with Markers**

***

## What This Workflow Solves

Lens & Tracking Calibration (Rotation Only) solves the lens behavior and the rotational tracking alignment together.

#### Lens Profile

The workflow creates a **Lens Profile**.

The Lens Profile describes the optical behavior of the lens, including distortion and zoom/focus-dependent calibration data.

#### Alignment Profile

The workflow creates an **Alignment Profile**.

The Alignment Profile aligns the incoming rotation data with the real optical camera image.

This is needed because the rotation tracking system or camera head may not perfectly match the real optical center and viewing direction of the camera.

#### Optional Calibration Screen Updates

The workflow can optionally update the placement, orientation, or shape of Calibration Screens.

However, because this workflow has limited camera movement, screen repositioning can be harder to solve reliably than with a freely moving tracked camera.

{% hint style="warning" %}
For rotation-only setups, it is often better to position the Calibration Screens first using **Screen Reposition Without Profile** or another workflow with more viewing variation. Then disable screen repositioning during the rotation-only calibration.
{% endhint %}

***

## Required Setup

Lens & Tracking Calibration (Rotation Only) requires a camera image, Calibration Screens, rotation data, and lens encoder values.

#### Required Inputs

The workflow requires:

* a **Media Input** with the raw camera image
* **Calibration Screens**
* rotation data, usually pan and tilt
* zoom and focus values as Custom Data
* a Calibration Object loaded with **Lens & Tracking Calibration (Rotation Only)**

#### Camera Object and Maps

The rotation and lens data should be mapped to the Camera Object first.

The Calibration Object then references the required map through:

```
Maps → Map List → Input Map
```

For this workflow, the map should provide:

| Required Data         | Map Option          |
| --------------------- | ------------------- |
| Rotation / Pan / Tilt | **Use Rot**         |
| Zoom / Focus          | **Use Custom Data** |

Position data is usually not required for this workflow.

{% hint style="info" %}
Zoom and focus values are handled as **Custom Data**.
{% endhint %}

#### Calibration Screens

Calibration Screens are used as the visual reference.

Make sure that:

* the correct Calibration Images are displayed
* the Calibration Images are not scaled, cropped, or distorted
* all required screens are added to the Calibration Object
* the screens are visible across a wide pan and tilt range
* screen placement is already reliable if screen repositioning is disabled

***

## Important Settings

Only the workflow-specific settings are listed here.

The exact UI setup is explained in the general Calibration Object pages.

#### Image

Select the Media Input that belongs to the camera being calibrated.

The image must be the raw camera signal.

#### Maps

Add the required map or maps to the Calibration Object.

Enable:

* **Use Rot** for pan / tilt / rotation data
* **Use Custom Data** for zoom and focus

Do not enable **Use Pos** unless the selected setup specifically requires it.

#### Reposition Screens

Use screen repositioning carefully.

Rotation-only setups provide less spatial variation than freely moving cameras. This can make it harder to calculate accurate Calibration Screen placement.

Disable screen repositioning when the Calibration Screens are already positioned correctly.

{% hint style="warning" %}
If Calibration Screens are already positioned, measured, or exported to another system, disable screen repositioning unless you intentionally want to update their placement.
{% endhint %}

#### User Outputs

Configure the outputs for:

* Lens Profile
* Alignment Profile
* optional Calibration Screen updates

Choose whether the profiles should be saved as new profiles, overwrite existing profiles, or be assigned to the Camera Object after calibration.

***

## Capture Strategy

The most important capture strategy for this workflow is to use as much of the available pan and tilt range as possible.

Because the camera position does not change significantly, the solver depends heavily on rotation variation.

#### Use the Full Pan Range

Pan the camera across the full range where it will be used.

Capture data from:

* far left views
* center views
* far right views
* intermediate pan angles

Do not only capture around the center position.

#### Use the Full Tilt Range

Tilt the camera through the full practical tilt range.

Capture data from:

* low tilt angles
* center tilt angles
* high tilt angles
* intermediate tilt positions

The goal is to show the Calibration Screens from many different viewing directions.

#### Combine Pan and Tilt

Do not capture pan and tilt separately only.

Use many combinations of pan and tilt so the solver sees the Calibration Screens from different angles.

For example:

* left + low
* left + high
* center + low
* center + high
* right + low
* right + high

{% hint style="info" %}
For rotation-only calibration, broad pan and tilt coverage is more important than collecting many captures from nearly the same viewing direction.
{% endhint %}

***

## Capture Zoom and Focus Range

Zoom and focus capture strategy is the same as for Lens & Tracking Calibration.

#### Zoom Lenses

For zoom lenses, capture data at important zoom positions.

Start with maximum zoom, then evaluate the zoom range and add data where the alignment error is greatest.

Useful zoom positions may include:

* maximum zoom
* minimum zoom
* positions where the alignment error is highest
* positions frequently used in production

#### Focus Positions

For focus-dependent calibration, start at infinity focus.

Then add additional stable focus positions where Calibration Pattern detection remains reliable.

Avoid focus positions where markers are too blurry or detection becomes unstable.

***

## Best Practices

This workflow works best when the rotation range is well covered and the Calibration Screens are clearly detected.

#### Maximize Rotation Variation

Use as much pan and tilt variation as possible.

Since the camera does not move freely through space, rotation coverage is the main source of geometric variation for the solver.

#### Use Reliable Calibration Screen Placement

If possible, use Calibration Screens that are already positioned accurately.

For limited movement systems, screen placement can be harder to solve during the same calibration.

A common workflow is:

1. Position the Calibration Screens first using **Screen Reposition Without Profile** with a separate camera.
2. Use the solved Calibration Screens for the rotation-only calibration.
3. Disable screen repositioning in the rotation-only workflow.

#### Use Raw Rotation and Lens Values

Use raw pan, tilt, zoom, and focus values whenever possible.

Avoid data where lens distortion, nodal shifts, or zoom/focus-dependent offsets are already applied.

Grid Studio needs raw values so it can create its own Lens Profile and Alignment Profile.

***

## Common Mistakes

Avoid these common problems during Lens & Tracking Calibration (Rotation Only).

#### Not Enough Pan / Tilt Coverage

If all captures are taken from similar pan and tilt angles, the calibration may not have enough useful variation.

Use the full practical rotation range.

#### Screen Repositioning with Limited Movement

Trying to reposition Calibration Screens with only a small pan/tilt range may produce weak results.

Use already positioned screens when possible.

#### Missing Zoom / Focus Custom Data

If **Use Custom Data** is disabled, zoom and focus values may not be available to the lens calibration.

Make sure zoom and focus are mapped correctly.

#### Using Position Data by Accident

This workflow is intended for rotation-only systems.

Do not enable **Use Pos** unless the setup specifically requires it.

#### Poor Marker Detection at Extreme Angles

At strong pan or tilt angles, Calibration Patterns may become harder to detect.

If detection becomes unstable, check:

* focus
* exposure
* marker size
* screen brightness
* viewing angle
* motion blur

***

## Outputs

Lens & Tracking Calibration (Rotation Only) can create the same main outputs as Lens & Tracking Calibration.

#### Lens Profile

The generated Lens Profile should be saved and assigned to the Camera Object that will use the calibrated lens.

#### Alignment Profile

The generated Alignment Profile should be saved and assigned to the same Camera Object.

This aligns the rotation data with the real optical camera image.

#### Calibration Screen Updates

If screen repositioning was enabled, check and save the updated Calibration Screen placement only if intended.

If the screens are used by Unreal Engine, a media server, or another external system, update or re-export the screen data there as needed.

***

## Before Continuing Checklist

Before using Lens & Tracking Calibration (Rotation Only), check the following:

* The camera uses rotation-only or mostly rotation-only tracking.
* Pan and tilt values are available.
* Zoom and focus values are available as Custom Data.
* The Media Input uses the raw camera image.
* Calibration Screens are visible and configured correctly.
* The correct maps are selected in the Calibration Object.
* **Use Rot** and **Use Custom Data** are enabled correctly.
* **Use Pos** is disabled unless specifically required.
* Screen repositioning is enabled only if screen placement should be updated.
* The capture data covers as much pan and tilt range as possible.
* The capture data covers the required zoom and focus range.
* Lens Profile and Alignment Profile outputs are configured.