autoExposureLensApertureRateLimit
Specifies a rate limit for aperture motion, whenever auto-exposure is active.
Declaration
var autoExposureLensApertureRateLimit: Float { get set }Discussion
This rate limit is enforced whenever the auto-exposure system has control of one or more exposure parameters, to ensure smooth transitions between target values with coordinated management of the automatically adjusted parameters to maintain image brightness. However, if a full set of explicit (not “auto”) positions are passed to setExposureModeCustomWithLensAperture:duration:ISO:completionHandler:, any change to aperture is immediately applied without rate limit. In this case, the client has full control of the exposure parameters, and can implement arbitrary exposure transitions by repeated calls to the setter.
This value limits the maximum frame-to-frame change of aperture size, as the ratio of aperture area between consecutive frames. For example, a value of 1.1 limits the aperture to accepting 10% additional light on each consecutive frame (or reducing by 10% when closing). A value of 1.0 does not allow any aperture motion. A special value of 0 (the default) allows the system to adjust the aperture speed automatically, such as faster motion in preview and slower when recording. When assigned to a value other than 0, the value must be greater than or equal to 1.0.
See Also
Configuring exposure manually
setExposureModeCustom(duration:iso:completionHandler:)setExposureModeCustom(lensAperture:duration:iso:completionHandler:)autoExposureDurationautoISOautoLensAperturecurrentLensApertureexposureDurationisolensApertureactiveMaxExposureDurationautomaticallyAdjustsExposureDurationautomaticallyAdjustsISOautomaticallyAdjustsLensAperture