Presenting camera permission dialog in iOS 8

I'm running into a similar issue, if the user has denied camera access when they are first prompted, pressing the button to take snapshot results in a black screen in the camera mode.

However I want to detect that the user has declined access and prompt them it must be turned on but I can't find any functions to check the current user camera access, is there such a function?

EDIT: The following check will let you know in IOS 8 about camera access:

#import <AVFoundation/AVFoundation.h>

AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    
    if(status == AVAuthorizationStatusAuthorized) { // authorized
        
    }
    else if(status == AVAuthorizationStatusDenied){ // denied
        
    }
    else if(status == AVAuthorizationStatusRestricted){ // restricted
        
        
    }
    else if(status == AVAuthorizationStatusNotDetermined){ // not determined
        
        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
            if(granted){ // Access has been granted ..do something
               
            } else { // Access denied ..do something
               
            }
        }];
    }

This information was found on the following question (How to know that application have camera access or not programmatically in iOS8):

Here is the approach we ended up using:

if ([AVCaptureDevice respondsToSelector:@selector(requestAccessForMediaType: completionHandler:)]) {
    [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
        // Will get here on both iOS 7 & 8 even though camera permissions weren't required 
        // until iOS 8. So for iOS 7 permission will always be granted.
        if (granted) {
            // Permission has been granted. Use dispatch_async for any UI updating
            // code because this block may be executed in a thread.
            dispatch_async(dispatch_get_main_queue(), ^{
                [self doStuff];
            });                
        } else {
            // Permission has been denied.
        }
    }];
} else {
    // We are on iOS <= 6. Just do what we need to do.
    [self doStuff];
}