How to know if device supports auto-focus

I would like to know if it exists a way to check if device camera supports auto-focus ?

The only solution I found is to check device name in order to know if it supports auto-focus or not. But I di开发者_运维百科d not like it because it did not work for future device.

---

Using the new AVFoundation APIs in iOS 4.0, you can check this by querying the AVCaptureDevice instance for the camera using its -isFocusModeSupported: method. The focus modes include AVCaptureFocusModeLocked, AVCaptureFocusModeAutoFocus, and AVCaptureFocusModeContinuousAutoFocus.