AVCamManual.AVCamManualCameraViewController.ExposureDurationChanged C# (CSharp) Method

		void ExposureDurationChanged (NSObservedChange obj)
		{
			var newValue = obj.NewValue;
			var oldValue = obj.OldValue;

			if (newValue != null && newValue != NSNull.Null) {
				double newDurationSeconds = newValue.AsCMTime ().Seconds;
				AVCaptureExposureMode exposureMode = VideoDevice.ExposureMode;

				double minDurationSeconds = Math.Max (VideoDevice.ActiveFormat.MinExposureDuration.Seconds, ExposureMinDuration);
				double maxDurationSeconds = VideoDevice.ActiveFormat.MaxExposureDuration.Seconds;
				// Map from duration to non-linear UI range 0-1
				double p = (newDurationSeconds - minDurationSeconds) / (maxDurationSeconds - minDurationSeconds); // Scale to 0-1
				DispatchQueue.MainQueue.DispatchAsync (() => {
					if (exposureMode != AVCaptureExposureMode.Custom)
						ExposureDurationSlider.Value = (float)Math.Pow(p ,1 / ExposureDurationPower); // Apply inverse power
					ExposureDurationValueLabel.Text = FormatDuration (newDurationSeconds);
				});
			}
		}