Fixed camera focus point, but intr… | Apple Developer Forums

Fixed camera focus point, but intrinsic is varying

I try to fix focus length for iPad camera, and get camera intrinsic value.
But fx, fy of camera intrinsics is varied.
Are fx and fy varied normal?

iOS version is 13.5.1

Code Block ObjectiveCAVCaptureConnection *conn = [dataOutput connectionWithMediaType:AVMediaTypeVideo];
if (conn.isCameraIntrinsicMatrixDeliverySupported) {
      [conn setCameraIntrinsicMatrixDeliveryEnabled: true];
}

Code Block ObjectiveC
AVCaptureConnection *conn = [dataOutput connectionWithMediaType:AVMediaTypeVideo];
if (conn.isCameraIntrinsicMatrixDeliverySupported) {
[conn setCameraIntrinsicMatrixDeliveryEnabled: true];
}

Code Block ObjectiveC- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
		CFTypeRef intrinsics_data_ref = CMGetAttachment(sampleBuffer,
                          kCMSampleBufferAttachmentKey_CameraIntrinsicMatrix,
                          nil);
  	NSData *intrinsics_data = (__bridge NSData *)intrinsics_data_ref;
  	matrix_float3x3 *intrinsics_3x3 = (matrix_float3x3 *)intrinsics_data.bytes;
  	float fx = intrinsics_3x3->columns[0][0];
  	float fy = intrinsics_3x3->columns[1][1];
  	float cx = intrinsics_3x3->columns[2][0];
  	float cy = intrinsics_3x3->columns[2][1];
  	NSLog(@"output: fx= %f, fy= %f, cx= %f, cy= %f", fx, fy, cx, cy);
}