... method 1. Locate, choose and attach the appropriate lens:The usable of the lenses diameter are 28mm, 38mm ... 15mm, please choose the IR-lamp temperature about 160-240°C, and choose the lens which D=28mm to ... 30mm, please choose the IR-lamp temperature about 240-320°C, and choose the lens which D=38mm to ... steady on the set-up temperature),and choose the lens which D=48mmto avoid destroying other places, and ...