Sample Video of the 4500mW IR Cannon going through adjustments manually.. the cannon is just a nickname, it could also be considered an IR Laser as this is basically what you'll find on those cameras.
Camera: 4MP Dahua w/6mm Optics (HFW4421D-AS)
Places to buy, these will get ~$60 on sale:
CCTV 5 90 Adjustable Focus 4500mW Surveillance IR Illuminator LED Array 850nm 10 100M-in CCTV Accessories from Security & Protection on Aliexpress.com | Alibaba Group
Surveillance Cameras Night Vision Fill Light 850nm Zoom IR LED Array 4500mW Light 15 100m Angle 5 80degree Manual Adjustment-in CCTV Accessories from Security & Protection on Aliexpress.com | Alibaba Group