21-917 25mm Dia. UVFS Aspheric Lens; EFL=50mm; NA=0.23 UV-VIS 250-700nm

The 21-917 is a high-quality aspheric lens, designed and manufactured by Edmund Optics. This lens is characterized by its 25mm diameter and a numerical aperture (NA) of 0.23, making it suitable for a wide range of applications. The lens is made from UV-VIS fused silica, a material known for its excellent transparency across the ultraviolet, visible, and near-infrared spectrum (250-700nm).

The lens features an effective focal length (EFL) of 50mm, which is the distance from the lens's principal point to its focal point. This EFL makes the lens suitable for use in imaging systems where a moderate focal length is required. The lens also has a relatively large clear aperture, which allows for a higher light-gathering capacity, resulting in improved image quality.

The 21-917 lens boasts a high-quality anti-reflection coating on both the front and back surfaces. This coating, known as the "edm uv-vis std curve", is designed to minimize surface reflections and increase transmission, thereby enhancing the overall performance of the lens.

The lens has a robust construction, with a thickness at the edge of 3.82mm and a center thickness of 7.2mm. This robust construction ensures the lens can withstand the rigors of regular use while maintaining its optical performance.