AVFoundation is just great for those who want to get hands dirty, but there still a lot of basic stuff not easy to figure like how to save the pictures taken from device to
Here is a step by step tutorial on how to capture an image using AVFoundation and save it to photo album.
Add a UIView object to the NIB (or as a subview), and create a @property in your controller:
@property(nonatomic, retain) IBOutlet UIView *vImagePreview;
Connect the UIView to the outlet above in IB, or assign it directly if you’re using code instead of a NIB.
Then edit your UIViewController, and give it the following viewDidAppear method:
-(void)viewDidAppear:(BOOL)animated
{
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    session.sessionPreset = AVCaptureSessionPresetMedium;
    CALayer *viewLayer = self.vImagePreview.layer;
    NSLog(@"viewLayer = %@", viewLayer);
    AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
    captureVideoPreviewLayer.frame = self.vImagePreview.bounds;
    [self.vImagePreview.layer addSublayer:captureVideoPreviewLayer];
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    NSError *error = nil;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
    if (!input) {
        // Handle the error appropriately.
        NSLog(@"ERROR: trying to open camera: %@", error);
    }
    [session addInput:input];
    stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
    NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
    [stillImageOutput setOutputSettings:outputSettings];
    [session addOutput:stillImageOutput];
    [session startRunning];
}
Create a new @property to hold a reference to output object:
@property(nonatomic, retain) AVCaptureStillImageOutput *stillImageOutput;
Then make a UIImageView where we’ll display the captured photo. Add this to your NIB, or programmatically.
Hook it up to another @property, or assign it manually, e.g.;
@property(nonatomic, retain) IBOutlet UIImageView *vImage;
Finally, create a UIButton, so that you can take the photo.
Again, add it to your NIB (or programmatically to your screen), and hook it up to the following method:
-(IBAction)captureNow {
    AVCaptureConnection *videoConnection = nil;
    for (AVCaptureConnection *connection in stillImageOutput.connections)
    {
        for (AVCaptureInputPort *port in [connection inputPorts])
        {
            if ([[port mediaType] isEqual:AVMediaTypeVideo] )
            {
                videoConnection = connection;
                break;
            }
        }
        if (videoConnection) 
            { 
                break; 
            }
    }
    NSLog(@"about to request a capture from: %@", stillImageOutput);
    [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
    {
         CFDictionaryRef exifAttachments = CMGetAttachment( imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
         if (exifAttachments)
         {
            // Do something with the attachments.
            NSLog(@"attachements: %@", exifAttachments);
         } else {
            NSLog(@"no attachments");
             }
        NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
        UIImage *image = [[UIImage alloc] initWithData:imageData];
        self.vImage.image = image;
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
     }];
}
You might have to import #import  also.
Source. Also check this.