---
title: fStop
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scncamera/fstop
---

# fStop

The physical camera aperture simulated by SceneKit for depth-of-field effects. Animatable.

## Declaration

```swift
var fStop: CGFloat { get set }
```

## Discussion

Discussion F-stop numbers describe the light-gathering area of a physical camera’s imaging system, and are typically expressed as the denominator of a ratio including the camera’s focal length ƒ, such as ƒ/2 or ƒ/5.6. A larger denominator indicates a smaller aperture, allowing less light to pass from the camera’s lens through to the imaging plane (sensor or film), and a smaller denominator indicates a larger aperture that lets more light through. SceneKit uses aperture measurements to simulate depth-of-field blur effects (also called bokeh) approximating those produced by a physical camera. A larger fStop number (or aperture denominator) causes most of the scene to appear in focus, with extremely close or far depths showing slight blurring; a smaller number results in only a narrow range of depths appearing in focus, and a more pronounced blur effect for the rest of the scene. The default fStop value is 5.6. You can animate changes to this property’s value. See Animating SceneKit Content.

## See Also

### Adding Depth-of-Field Effects

- [wantsDepthOfField](scenekit/scncamera/wantsdepthoffield.md)
- [focusDistance](scenekit/scncamera/focusdistance.md)
- [apertureBladeCount](scenekit/scncamera/aperturebladecount.md)
- [focalBlurSampleCount](scenekit/scncamera/focalblursamplecount.md)