Instance Property


The maximum exposure duration, in seconds, defined in the auto-exposure algorithm.


var activeMaxExposureDuration: CMTime { get set }


When you set a new session preset on your capture session or select a different activeFormat on your capture device, you can query or observe changes to activeMaxExposureDuration.

You can override this property at any time, to any value in the activeFormat property’s minExposureDuration and maxExposureDuration range. Changes are reflected immediately while the session is running, with no graph rebuilding. You can also set the property to invalid to return to the default value. For example, one case in which you'd override the auto-exposure algorithm's maximum exposure duration is if you want shorter exposure than your frame rate. If you need to freeze motion by exposing for 1/40th of a second but still capture 30 frames a second, then a manual override is needed.

See Also

Managing Image Exposure

var exposureDuration: CMTime

The length of time over which exposure takes place.

var exposureTargetOffset: Float

The metered exposure level's offset from the target exposure value, in EV units.

var exposureTargetBias: Float

Bias applied to the target exposure value, in EV units.

var minExposureTargetBias: Float

The minimum supported exposure bias, in EV units.

var maxExposureTargetBias: Float

The maximum supported exposure bias, in EV units.

func setExposureTargetBias(Float, completionHandler: ((CMTime) -> Void)?)

Sets the bias to be applied to the target exposure value.

class let currentExposureTargetBias: Float

A special constant representing the current exposure bias value.

class let currentExposureDuration: CMTime

A special constant representing the current exposure duration setting.

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