Which device is used to shape the beam of light in a lantern?

The device used to shape the beam of light in a lantern is the lens. A lens can converge or diverge light rays, effectively controlling the focus and shape of the light emitted from the lantern. This ability to alter the direction and spread of light makes lenses essential in various lighting applications, including theater productions and performances.

In contrast, diffusers are used to soften and scatter light rather than shape it. Barndoors control the shaping of the beam by blocking portions of light, but they are not primarily used for shaping in the same way a lens is. Filters adjust the color of the light but do not influence its shape. Understanding the specific roles of these devices in lighting design helps clarify why the lens is the appropriate choice for shaping the beam of light.