Auto-Iris Varifocal Camera LensesVarifocals have a to and from range, most typically cover somewhere between 2.8 and 12mm. For long-distance surveillance like license plate recognition cameras, a range of 5 to 60mm is common. The key benefit to a varifocal camera is the flexibility this gives you during installation. They allow you to adjust the lens between the top and bottom limits of its view angle. This flexibility does come with an increase in cost.