Static AVCaptureDeviceTypeBuiltInDualCamera 

pub unsafe static AVCaptureDeviceTypeBuiltInDualCamera: &'static AVCaptureDeviceType

Available on crate feature AVCaptureDevice only.

A device that consists of two fixed focal length cameras, one wide and one telephoto. Note that devices of this type may only be discovered using an AVCaptureDeviceDiscoverySession or -[AVCaptureDevice defaultDeviceWithDeviceType:mediaType:position:].

A device of this device type supports the following features:

• Auto switching from one camera to the other when zoom factor, light level, and focus position allow this.
• Higher quality zoom for still captures by fusing images from both cameras.
• Depth data delivery by measuring the disparity of matched features between the wide and telephoto cameras.
• Delivery of photos from constituent devices (wide and telephoto cameras) via a single photo capture request.

A device of this device type does not support the following features:

• AVCaptureExposureModeCustom and manual exposure bracketing.
• Locking focus with a lens position other than AVCaptureLensPositionCurrent.
• Locking auto white balance with device white balance gains other than AVCaptureWhiteBalanceGainsCurrent.

Even when locked, exposure duration, ISO, aperture, white balance gains, or lens position may change when the device switches from one camera to the other. The overall exposure, white balance, and focus position however should be consistent.

See also Apple’s documentation