IOS11 camera slow response

I have this problem since upgrading to IOS11. I have made all updates. It is on IOS11.1.1 now. The symptom is slow response under "photo" mode. Sometimes (less than 50%) when I open the camera app to default "photo" mode, or switch from other mode (mostly "portrait"), the screen becomes dark, out of focus, slowly updating with the picture. I can switch to other modes. "Video" is fine, "portrait" is fine. "Square" has the same issue. After a while of switching back and forth, this issue goes away. This is a big problem when I want to take group photos. Everyone is waiting for me, but I have to wait for the camera to behave.

I have done factory reset multiple times. It didn't help.

I didn't have this issue before upgrading to IOS11.