# Exposure Configure the automatic exposure behavior of a camera, or manually control its exposure settings. ## Topics ### Managing the exposure mode [`- isExposureModeSupported:`](/documentation/AVFoundation/AVCaptureDevice/isExposureModeSupported(_:)) Returns a Boolean value that indicates whether a device supports the specified exposure mode. [`exposureMode`](/documentation/AVFoundation/AVCaptureDevice/exposureMode-swift.property) The exposure mode for the device. [`ExposureMode`](/documentation/AVFoundation/AVCaptureDevice/ExposureMode-swift.enum) Constants that specify the exposure mode of a capture device. ### Setting an exposure point of interest [`exposurePointOfInterestSupported`](/documentation/AVFoundation/AVCaptureDevice/isExposurePointOfInterestSupported) A Boolean value that indicates whether the device supports a point of interest for exposure. [`exposurePointOfInterest`](/documentation/AVFoundation/AVCaptureDevice/exposurePointOfInterest) The point of interest for exposure. ### Setting an exposure rectangle of interest [`exposureRectOfInterestSupported`](/documentation/AVFoundation/AVCaptureDevice/isExposureRectOfInterestSupported) Whether the device supports exposure rectangles of interest. [`exposureRectOfInterest`](/documentation/AVFoundation/AVCaptureDevice/exposureRectOfInterest) The device’s current exposure rectangle of interest, if it has one. [`minExposureRectOfInterestSize`](/documentation/AVFoundation/AVCaptureDevice/minExposureRectOfInterestSize) The minimum size you may use when specifying a rectangle of interest. [`- defaultRectForExposurePointOfInterest:`](/documentation/AVFoundation/AVCaptureDevice/defaultRectForExposurePoint(ofInterest:)) The default rectangle of interest used for a given exposure point of interest. ### Configuring face-driven automatic exposure [`faceDrivenAutoExposureEnabled`](/documentation/AVFoundation/AVCaptureDevice/isFaceDrivenAutoExposureEnabled) A Boolean value that indicates whether the device has face-driven autoexposure enabled. [`automaticallyAdjustsFaceDrivenAutoExposureEnabled`](/documentation/AVFoundation/AVCaptureDevice/automaticallyAdjustsFaceDrivenAutoExposureEnabled) A Boolean value that indicates whether the device automatically adjusts face-driven autoexposure. ### Monitoring exposure changes [`adjustingExposure`](/documentation/AVFoundation/AVCaptureDevice/isAdjustingExposure) A Boolean value that indicates whether the device is currently adjusting its exposure setting. ### Adjusting exposure compensation [`exposureTargetOffset`](/documentation/AVFoundation/AVCaptureDevice/exposureTargetOffset) The metered exposure level’s offset from the target exposure value, in exposure value (EV) units. [`exposureTargetBias`](/documentation/AVFoundation/AVCaptureDevice/exposureTargetBias) The bias to apply to the target exposure value, in exposure value (EV) units. [`minExposureTargetBias`](/documentation/AVFoundation/AVCaptureDevice/minExposureTargetBias) The minimum supported exposure bias, in exposure value (EV) units. [`maxExposureTargetBias`](/documentation/AVFoundation/AVCaptureDevice/maxExposureTargetBias) The maximum supported exposure bias, in exposure value (EV) units. [`AVCaptureExposureTargetBiasCurrent`](/documentation/AVFoundation/AVCaptureDevice/currentExposureTargetBias) A special constant that represents the current exposure bias value. [`- setExposureTargetBias:completionHandler:`](/documentation/AVFoundation/AVCaptureDevice/setExposureTargetBias(_:completionHandler:)) Sets the bias to apply to the target exposure value. ### Configuring exposure manually [`- setExposureModeCustomWithDuration:ISO:completionHandler:`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(duration:iso:completionHandler:)) Sets the exposure mode to a custom state, and locks exposure duration and ISO at explicit values. [`- setExposureModeCustomWithLensAperture:duration:ISO:completionHandler:`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(lensAperture:duration:iso:completionHandler:)) Sets a custom exposure mode with the specified lens aperture, exposure duration, and ISO values. [`AVCaptureExposureDurationAuto`](/documentation/AVFoundation/AVCaptureDevice/autoExposureDuration) A special value that may be passed as the duration parameter of a device’s `setExposureModeCustom...` methods to allow the system’s auto-exposure system to manage the exposure duration. [`AVCaptureISOAuto`](/documentation/AVFoundation/AVCaptureDevice/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. [`AVCaptureLensApertureAuto`](/documentation/AVFoundation/AVCaptureDevice/autoLensAperture) A special value that may be passed as the lensAperture parameter of a device’s `setExposureModeCustom...` methods to allow the system’s auto-exposure system to manage the aperture. [`AVCaptureLensApertureCurrent`](/documentation/AVFoundation/AVCaptureDevice/currentLensAperture) A special value that may be passed as the lensAperture parameter of a device’s `setExposureModeCustom...` methods to lock at the current position. [`exposureDuration`](/documentation/AVFoundation/AVCaptureDevice/exposureDuration) The length of time over which exposure takes place. [`ISO`](/documentation/AVFoundation/AVCaptureDevice/iso) The current exposure ISO value. [`lensAperture`](/documentation/AVFoundation/AVCaptureDevice/lensAperture) The size of the lens diaphragm. [`activeMaxExposureDuration`](/documentation/AVFoundation/AVCaptureDevice/activeMaxExposureDuration) The maximum exposure duration, in seconds, defined in the autoexposure algorithm. [`automaticallyAdjustsExposureDuration`](/documentation/AVFoundation/AVCaptureDevice/automaticallyAdjustsExposureDuration) This property reports true whenever exposureDuration is unlocked, either by setting exposureMode to one of the automatic modes, or by passing `AVCaptureExposureDurationAuto` to the duration parameter of [`setExposureModeCustom(duration:iso:completionHandler:)`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(duration:iso:completionHandler:)) or [`setExposureModeCustom(lensAperture:duration:iso:completionHandler:)`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(lensAperture:duration:iso:completionHandler:)). [`automaticallyAdjustsISO`](/documentation/AVFoundation/AVCaptureDevice/automaticallyAdjustsISO) This property reports true whenever ISO is unlocked, either by setting exposureMode to one of the automatic modes, or by passing `AVCaptureISOAuto` to the ISO parameter of [`setExposureModeCustom(duration:iso:completionHandler:)`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(duration:iso:completionHandler:)) or [`setExposureModeCustom(lensAperture:duration:iso:completionHandler:)`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(lensAperture:duration:iso:completionHandler:)). [`automaticallyAdjustsLensAperture`](/documentation/AVFoundation/AVCaptureDevice/automaticallyAdjustsLensAperture) This property reports true whenever lensAperture is unlocked, either by setting exposureMode to one of the automatic modes, or by passing `AVCaptureLensApertureAuto` to the aperture parameter of [`setExposureModeCustom(lensAperture:duration:iso:completionHandler:)`](/documentation/AVFoundation/AVCaptureDevice/setExposureModeCustom(lensAperture:duration:iso:completionHandler:)). [`autoExposureLensApertureRateLimit`](/documentation/AVFoundation/AVCaptureDevice/autoExposureLensApertureRateLimit) Specifies a rate limit for aperture motion, whenever auto-exposure is active. ### Configuring exposure signals [`activeExposureSignals`](/documentation/AVFoundation/AVCaptureDevice/activeExposureSignals) Reports which characteristics the auto exposure system associates with the current scene. Auto exposure may adjust properties such as lens aperture size based on these factors. This property is key-value observable. [`enabledExposureSignals`](/documentation/AVFoundation/AVCaptureDevice/enabledExposureSignals) Can be assigned to control which characteristics AE should use in its decision making, must be a subset of supportedExposureSignals. [`supportedExposureSignals`](/documentation/AVFoundation/AVCaptureDevice/supportedExposureSignals) Indicates what values can be included in `enabledExposureSignals`. This property is key-value observable. [`automaticallyEnablesExposureSignals`](/documentation/AVFoundation/AVCaptureDevice/automaticallyEnablesExposureSignals) When true (the default), capture sessions may automatically modify `enabledExposureSignals` based on changes to other device or session properties. [`AVCaptureDeviceExposureSignal`](/documentation/AVFoundation/AVCaptureDeviceExposureSignal) Values that can be used to configure the auto exposure system via [`enabledExposureSignals`](/documentation/AVFoundation/AVCaptureDevice/enabledExposureSignals) and associated methods. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)