What makes bifocals glasses cheaper than varifocal?
High Quality 5-50mm 6-60mm 2.8-12mm Megapixel Varifocal Lens Manual Zoom & Focus CS Mount CCTV Lens for CCTV Security Camera - AliExpress
D14 EFL 2.8-12mm manual focus varifocal lens for 1/3" sensor 120 to 36 degree adjustable for CCTV camera HD 3MP zoom lens - AliExpress
Computar 3.5-8mm Varifocal Lens | eBay
Dahua PFL0550-E6D 6MP 5 mm to 50 mm Vari-focal Lens
Amazon.com: ELP 5-50mm Varifocal Lens 1080P USB Camera with H.264 High Definition Sony IMX323 Webcam for Android Linux Windows Industrial Video : Electronics
Marshall Electronics - Optical Systems Division - CS Mount Varifocal Lenses with DC Auto Iris
Different types of varifocal lenses | Banton Frameworks
Bosch LVF-5003C-P2713 Varifocal lens, 2.7-13mm, 3MP, CS mount | eBay
Samsung 1/3" 5-50mm 1:1.7 f1.7 CS Mount Varifocal Lens - F/S from USA | eBay
Lenses buyers guide | Vision Express
Amazon.com: Hotpet 8 Megapixel USB Camera 2.8-12mm Varifocal Lens Webcam HD 3264X2448 Web Camera with Sony IMX179 Image Sensor Mini Industrial Camera Outdoor Indoor Web Cams Plug&Play, Support UVC OTG 2.0 : Electronics
Best Varifocal Lenses for Glasses - Oldfields Opticians
Amcrest UltraHD 4K Varifocal PoE Dome Outdoor Security Camera, 8MP 3264x2448, 164ft Night Vision, Motorized Varifocal Lens 58º-110º, White (IP8M-2454EW)