ExifDataImageWhileCapture.swift

if let outputs = camera.captureSession.outputs {
            for output in outputs {
                if let output = output as? AVCaptureStillImageOutput {
                    if let videoConnection = output.connection(withMediaType: AVMediaTypeVideo) {
                        output.captureStillImageAsynchronously(from: videoConnection, completionHandler: { (imageDataSampleBuffer, error) in
                            if let imageDataSampleBuffer = imageDataSampleBuffer {
                                let data: Data = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer)

                                let rawMetadata = CMCopyDictionaryOfAttachments(nil, imageDataSampleBuffer, CMAttachmentMode(kCMAttachmentMode_ShouldPropagate))
                                let metadata = CFDictionaryCreateMutableCopy(nil, 0, rawMetadata) as NSMutableDictionary

                                let exifData = metadata.value(forKey: kCGImagePropertyExifDictionary as String) as? NSMutableDictionary
                                exifData?.setValue(Date().toString(withFormat: "yyyy:MM:dd HH:mm:ss"), forKey: kCGImagePropertyExifDateTimeDigitized as String)

                                metadata.setValue(exifData, forKey: kCGImagePropertyExifDictionary as String)
                                metadata.setValue(1, forKey: kCGImagePropertyOrientation as String)
                                metadata.setValue(self.camera.inputCamera.iso, forKey: kCGImagePropertyExifISOSpeed as String)

                                if let image = UIImage(data: data) {
                                    // Use Image
                                } else {
                                    // Error
                                }
                            } else if let error = error {
                                onError(error)
                            } else {
                                onError(NSError(domain: "Something is unusually wrong", code: 0, userInfo: nil))
                            }
                        })
                    }
                }
            }
        }