# glTF 2.0 perspective cameras carry only aspectRatio, yfov, zfar and znear, so converting a physical camera (focal length, apertures, offsets) to glTF keeps only field of view and ratio; recovering focal length from glTF needs sensor size supplied out of...

- id: art_01M5NGX492R821Z642R4PV1Z7M
- 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, T15, T19 · tags: none
- updated: 2026-10-23T23:17:59.197Z
- url: https://veyrul.com/articles/art_01M5NGX492R821Z642R4PV1Z7M

glTF 2.0 perspective cameras carry only aspectRatio, yfov, zfar and znear, so converting a physical camera (focal length, apertures, offsets) to glTF keeps only field of view and ratio; recovering focal length from glTF needs sensor size supplied out of band.

glTF 2.0 perspective cameras carry only aspectRatio, yfov, zfar and znear, so converting a physical camera (focal length, apertures, offsets) to glTF keeps only field of view and ratio; recovering focal length from glTF needs sensor size supplied out of band.

Curator qualifications: UsdGeomCamera attribute list, Alembic unit mix, axis-convention comparison and HdCamera distortion fields (F0, F3-F6) not reinspected (OpenTrackIO axis convention verified separately in CA-B042). Static reading only.

Limitations: Static reading only.

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

```json
{
  "citations": [
    {
      "url": "https://github.com/pixaranimationstudios/openusd",
      "note": "cited at https://github.com/PixarAnimationStudios/OpenUSD; glTF camera.perspective.schema.json at 7cee0fcd"
    },
    {
      "url": "https://github.com/PixarAnimationStudios/OpenUSD",
      "note": "observed URL (dated/alias form of the cited catalogue source; canonical identity retained)"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] glTF 2.0 perspective cameras carry only aspectRatio, yfov, zfar and znear, so converting a physical camera (focal length, apertures, offsets) to glTF keeps only field of view and ratio; recovering focal length from glTF needs sensor size supplied out of band. · locator: cited at https://github.com/PixarAnimationStudios/OpenUSD; glTF camera.perspective.schema.json at 7cee0fcd · source: https://github.com/pixaranimationstudios/openusd

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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