iOS Camera permissions doesn't appear under settings in some devices

You need to request permission before opening a session. Use

[AVCaptureDevice requestAccessForMediaType:completionHandler:]

Step 1: Give a proper camera message access message on your info.plist using the following key (without quotes)

"Privacy - Camera Usage Description"

Step 2 : For objective-C/SWIFT you need to request a camera access permission

OBJECTIVE-C

[AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted)
        {
            if (granted == true)
            {
                //[self presentViewController           : picker animated:YES completion:NULL];
               //Do your stuff

            }
            else
            {
                UIAlertView *cameraAlert = [[UIAlertView alloc]initWithTitle:STR_APPLICATION_TITLE
                                                                     message:STR_ALERT_CAMERA_DENIED_MESSAGE
                                                                    delegate:self
                                                           cancelButtonTitle:@"OK"
                                                           otherButtonTitles:nil,nil];
                [cameraAlert show];

                NSLog(@"denied");
            }

        }];

SWIFT

AVCaptureDevice.requestAccessForMediaType(AVMediaTypeVideo, completionHandler: { (videoGranted: Bool) -> Void in
        if (videoGranted) {
             //Do Your stuff here

        } else {
            // Rejected Camera
        }
    })