What is the difference between having a lens and not having a lens?

[Nolan]

The differences between having a lens and not having a lens are: 1. Difference in light brightness: A lens can focus the light, allowing the car to achieve excellent lighting effects; lights without a lens tend to scatter, producing a more glaring light that can easily affect other drivers' vision and road safety. 2. Difference in field of view: A lens can provide the driver with a wider field of view and also enhance the car's aesthetics; without a lens, the driver's field of view is narrower. There are two types of lenses: single-beam lenses and dual-beam lenses. A single-beam lens can only control one bulb, with separate low and high beams; a dual-beam lens uses an internal shutter to control both light sources—high and low beams—allowing for seamless switching between them.