Kindly try some troubleshooting tips below:
1. Does the issue appear right after any apps' download or update?
2. Does the issue appear on the stock camera only or on other camera apps (e,g. Instagram) as well?
Please try clearing cache & storage of Camera (long press "Camera">App Info>Storage & memory>Clear cache/Clear storage), then try to re-install 3rd party camera apps and check again.
3. Also, if that doesnt help I will suggest you to try a to Factory Reset your device. Please note that you should back uo your data otherwise this will delete it.
Settings>System>Reset options>Erase all data(factory reset)
4.You can also check on SMMI test:
Calculator> type ".12345+=">SMMI TEST>Single Test>Wide-angled Camera Capture Test/Tele Camera Capture Test/Front Camera Capture Test
If any of the SMMI tests fails, indicating high possibility of faulty hardware, kindly bring your device to your nearest ASUS service center for getting your device check: https://www.asus.com/support/Service-Center-All-Countries/