ArduCam IMX519 slow (30 fps, but the image is noticeable late) on Raspberry Pi 4B 2GB RAM

I use Raspberry Pi 4B with 2 GB of RAM and IMX519.

What I’ve did:

  1. Follow the starter guide to install libcamera, that’s it 519操作手册说明书 (
  2. run this command libcamera-still -t 0
  3. put hand on top of the camera. It takes 5 seconds for the hand to appear.

Things that may cause this:

  1. Low voltage warning. Please check your power supply. I will test this tomorrow or the day after tomorrow when the Adaptor arrived.

What I’ve tried:

  1. libcamera-still -t 0 --framerate 1. The delay is considerably shorter. 2 seconds before the hand appear.

I would like to know what way you use to connect to your Raspberry Pi. Just connect your pi directly to the monitor or via VNC?

I use VNC (both through RJ45 cable or WiFi). I also tried with HDMI directly to the Raspberry Pi 4B, and it is smooth butter. The problem is I don’t have 2nd monitor, so I plan to buy a USB 2.0 to HDMI video capture device.