Notifies the delegate that photo capture is about to occur.
- iOS 10.0+
- macOS 10.15+
- Mac Catalyst 13.0+
The photo output performing the capture.
An object describing the settings used for this capture. Match this object’s
uniquevalue to the
uniqueproperty of the photo settings object you initiated capture with to determine which capture request this delegate call corresponds to. You can also use this object to find out which values the photo output has chosen for automatic settings.
The photo output calls this method as close as possible to the initial moment of capture. If the shutter sound is enabled, this call occurs immediately after the photo output begins playing the shutter sound.