49-396 50 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=500mm VIS-NIR 400-1000nm

The 49-396 is a high-quality achromatic doublet lens, boasting a 50 mm diameter and a focal length of 500mm, specifically designed for the visual and near-infrared spectrum (400-1000nm). This lens is sourced from the renowned optical vendor, Edmund Optics, and is a testament to their commitment to precision and quality.

The lens is constructed from two types of Schott glass, N-BK7 and N-SF5, which are renowned for their excellent optical properties. The N-BK7, a borosilicate crown glass, is known for its low dispersion and high transmission in the visible spectrum. The N-SF5, a dense flint glass, has a high refractive index and is used to correct chromatic aberration. This combination results in a lens with superior imaging capabilities and minimal color fringing.

The lens features a robust geometry, with a thickness of 10.51mm at the edge and 8mm at the center. The center thickness is further reduced to 4mm in the 'a' position, providing additional design flexibility. The lens also has a zero inner radius and a zero outer radius, indicating a simple, two-element design.

The lens is coated with Edmund Optics' VIS-NIR coating (edm visnir0sp2002000), which is applied to both the front and back surfaces. This coating is designed to enhance the lens's performance in the visual and near-infrared spectrum, reducing surface reflections and increasing transmission.