通过设置图片控制器UIImagePickerController的来源为UIImagePickerControllerSourceType.Camera，便可以打开相机

import UIKit

class ViewController: UIViewController, UIImagePickerControllerDelegate,
UINavigationControllerDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
    }    
    //拍照
    @IBAction func fromPhotograph(sender: AnyObject) {
        if UIImagePickerController.isSourceTypeAvailable(.Camera){
            //创建图片控制器
            let picker = UIImagePickerController()
            //设置代理
            picker.delegate = self
            //设置来源
            picker.sourceType = UIImagePickerControllerSourceType.Camera
            //允许编辑
            picker.allowsEditing = true
            //打开相机
            self.presentViewController(picker, animated: true, completion: { () -> Void in
                
            })
        }else{
            println("找不到相机")
        }
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}

2，调用前置，后置摄像头

//如果有前置摄像头则调用前置摄像头
if UIImagePickerController.isCameraDeviceAvailable(UIImagePickerControllerCameraDevice.Front){
	picker.cameraDevice = UIImagePickerControllerCameraDevice.Front
}

3，设置闪光灯
通过cameraFlashMode属性可以设置闪光灯：开启/关闭/自动

//开启闪光灯
picker.cameraFlashMode = UIImagePickerControllerCameraFlashMode.On