@riyumatters Hi dear, Then it's a different question. Part of H2 lens is made of resin material, the focus would lose a little as the temperature goes higher. So would recommend you to do the focus in 20 minutes' use. It would be quite stable then. And H2 has the dynamic focal length compensation, it would help to focus on the background while using. : Setup-system setting-Focus setting-dynamic focal length compensation