How to change lens in besder ip camera?

Question

CCTV

Good afternoon!
There are two such cameras. hanging in a very inconvenient place (I can’t make out).
https://www.aliexpress.com/item/BESDER-Yoosee-IP-C...
Those who know the question - Ali is full of lenses over 12mm. What is the lens size for this camera?
And the second point - how to calculate the focal length? The object of observation is a car. Floor - 9th. Now it costs 8mm, but it feels like you want a little closer to read numbers well and faces.

Answer 1

Facepalm!
1. Lens size 3.6mm.
2. 9 floors is 30-36 m.
https://www.beward.ru/calculators/ At the very bottom
https://systemssec.ru/info/calc/vychislenie-fokusn...
https://hikvision.ru /project/calc
Google CCTV focal length calculator.