@chinkung 

Hi,
In this case, can you share the pictures of the Tapo C100 V2 & V4 Live View page when they work in the Night mode at the same location for a comparison?

Please send me(Solla-topee) the MAC address of your Tapo C100 V2 & v4 via a private message.
Best Regards

  @chinkung 

Hi,
Thank you for the information you provided. After investigation, it's confirmed that Tapo C100 V4 and V2 are different in hardware and design, so the image effects are also different. The Tapo C100 V4 doesn't have a problem with the image, from the pictures, the color of the Tapo C100 V4 may not be as contrasty as V2, but the video quality does not have much difference.
Best Regards