---
title: "focalLength(at:error:)"
framework: Professional Video Applications
role: symbol
role_heading: Instance Method
platforms: [fxplug 4.1+]
path: "professional_video_applications/fx3dapi_v5/focallength(at:error:)"
---

# focalLength(at:error:)

Gets the focal length.

## Declaration

```swift
func focalLength(at time: CMTime, error: NSErrorPointer) -> Double
```

## Parameters

- `time`: Specified time, expressed as a doc://com.apple.documentation/documentation/CoreMedia/CMTime, to retrieve the matrix value.
- `error`: Description of the problem if you are unable to retrieve the value.

## Return Value

Return Value The value of the focal length.

## See Also

### Accessing the 3D Environment

- [layerMatrix(at:)](professional_video_applications/fx3dapi_v5/layermatrix(at:).md)
- [viewMatrix(at:)](professional_video_applications/fx3dapi_v5/viewmatrix(at:).md)
- [metalProjectionMatrix(at:)](professional_video_applications/fx3dapi_v5/metalprojectionmatrix(at:).md)
- [frustumLeft(_:right:bottom:top:near:far:at:)](professional_video_applications/fx3dapi_v5/frustumleft(_:right:bottom:top:near:far:at:).md)