---
title: minimumExposure
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scncamera/minimumexposure
---

# minimumExposure

The minimum exposure value to use in tone mapping.

## Declaration

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

## Discussion

Discussion When using a High Dynamic Range (HDR) camera, SceneKit applies a process called tone mapping to translate the wide range of luminance values in the visible scene to the narrower range of brightness values that can be shown on a display. SceneKit determines a tone mapping curve from the minimumExposure, maximumExposure, exposureOffset, and whitePoint properties, along with a measure of scene luminance. Exposure values are exponential: a value of 1.0 doubles brightness, a value of 2.0 quadruples brightness, a value of -1.0 halves brightness, and so on. The default value is -15.0. Increasing the value causes darker portions of the scene to become under-exposed (uniformly black, losing definition). Decreasing the value adds more dynamic range for darker portions of the scene; however, a greater breadth of difference between the minimum and maximum exposures decreases contrast. This property has no effect if the wantsHDR value is false.

## See Also

### Adding High Dynamic Range Effects

- [wantsHDR](scenekit/scncamera/wantshdr.md)
- [exposureOffset](scenekit/scncamera/exposureoffset.md)
- [averageGray](scenekit/scncamera/averagegray.md)
- [whitePoint](scenekit/scncamera/whitepoint.md)
- [maximumExposure](scenekit/scncamera/maximumexposure.md)