# What does an Unreal Engine Lens File store, what inputs does it need to be calibrated, and how is it evaluated at runtime?

- id: art_01M5MRH1JV5KWEBXVX7RSDJD5S
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T02, T12, T19 · tags: none
- updated: 2026-10-23T16:11:57.330Z
- url: https://veyrul.com/articles/art_01M5MRH1JV5KWEBXVX7RSDJD5S

Unreal's Lens File stores five Brown-Conrady distortion parameters (K1, K2, P1, P2, K3), camera intrinsics and nodal point offsets keyed by focus and zoom, interpolated between calibrated points; Epic says to make a new Lens File for each lens and camera body combination.

Unreal's Lens File stores five Brown-Conrady distortion parameters (K1, K2, P1, P2, K3), camera intrinsics and nodal point offsets keyed by focus and zoom, interpolated between calibrated points; Epic says to make a new Lens File for each lens and camera body combination.

Curator qualifications: Documentation read 2026-10-22; no lens calibrated. ST Map support, Live Link requirement for nodal offset and Python API from producer reading.

Limitations: Documentation read 2026-10-22; no lens calibrated.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://dev.epicgames.com/documentation/en-us/unreal-engine/camera-lens-calibration-overview",
      "note": "Epic docs: Camera Lens Calibration overview (live); Epic docs: Camera Lens Calibration quick start (live)"
    },
    {
      "url": "https://dev.epicgames.com/documentation/en-us/unreal-engine/camera-lens-calibration-quick-start-for-unreal-engine",
      "note": "Epic docs: Camera Lens Calibration overview (live); Epic docs: Camera Lens Calibration quick start (live)"
    },
    {
      "url": "https://dev.epicgames.com/documentation/en-us/unreal-engine/camera-lens-calibration-for-production?application_version=4.27",
      "note": "Epic docs: Camera Lens Calibration overview (live); Epic docs: Camera Lens Calibration quick start (live)"
    },
    {
      "url": "https://dev.epicgames.com/documentation/en-us/unreal-engine/python-api/class/LensFile?application_version=5.4",
      "note": "Epic docs: Camera Lens Calibration overview (live); Epic docs: Camera Lens Calibration quick start (live)"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Unreal's Lens File stores five Brown-Conrady distortion parameters (K1, K2, P1, P2, K3), camera intrinsics and nodal point offsets keyed by focus and zoom, interpolated between calibrated points; Epic says to make a new Lens File for each lens and camera body combination. · locator: Epic docs: Camera Lens Calibration overview (live); Epic docs: Camera Lens Calibration quick start (live) · source: https://dev.epicgames.com/documentation/en-us/unreal-engine/camera-lens-calibration-overview

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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