---
title: autoISO
framework: AVFoundation
role: symbol
role_heading: Type Property
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, tvOS 27.0+]
path: avfoundation/avcapturedevice/autoiso
---

# autoISO

A special value that may be passed as the ISO parameter of a device’s setExposureModeCustom... methods to allow the system’s auto-exposure system to manage the gain value.

## Declaration

```swift
class let autoISO: Float
```

## Discussion

Discussion This value may be passed to setExposureModeCustom(duration:iso:completionHandler:) or setExposureModeCustom(lensAperture:duration:iso:completionHandler:) to enable “priority” modes, where some parameters are locked to specified values (given “priority”), whereas the ones specified as “auto” will be continually adjusted by the system to maintain image brightness.

## See Also

### Configuring exposure manually

- [setExposureModeCustom(duration:iso:completionHandler:)](avfoundation/avcapturedevice/setexposuremodecustom(duration:iso:completionhandler:).md)
- [setExposureModeCustom(lensAperture:duration:iso:completionHandler:)](avfoundation/avcapturedevice/setexposuremodecustom(lensaperture:duration:iso:completionhandler:).md)
- [autoExposureDuration](avfoundation/avcapturedevice/autoexposureduration.md)
- [autoLensAperture](avfoundation/avcapturedevice/autolensaperture.md)
- [currentLensAperture](avfoundation/avcapturedevice/currentlensaperture.md)
- [exposureDuration](avfoundation/avcapturedevice/exposureduration.md)
- [iso](avfoundation/avcapturedevice/iso.md)
- [lensAperture](avfoundation/avcapturedevice/lensaperture.md)
- [activeMaxExposureDuration](avfoundation/avcapturedevice/activemaxexposureduration.md)
- [automaticallyAdjustsExposureDuration](avfoundation/avcapturedevice/automaticallyadjustsexposureduration.md)
- [automaticallyAdjustsISO](avfoundation/avcapturedevice/automaticallyadjustsiso.md)
- [automaticallyAdjustsLensAperture](avfoundation/avcapturedevice/automaticallyadjustslensaperture.md)
- [autoExposureLensApertureRateLimit](avfoundation/avcapturedevice/autoexposurelensapertureratelimit.md)