47-649 25 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=300mm VIS 0° 425-675nm

The 47-649 is a high-quality achromatic doublet lens, boasting a 25 mm diameter and an effective focal length of 300mm, specifically designed for the visible light spectrum ranging from 425 to 675nm. This lens is sourced from the renowned optical vendor, Edmund Optics, and is available for purchase through their website.

The lens is constructed from two types of glass, N-BK7 and N-SF5, both from Schott, ensuring excellent optical performance. The N-BK7, a borosilicate crown glass, is known for its low dispersion and high transmission, making it ideal for use in achromatic doublets. The N-SF5, a dense flint glass, further reduces chromatic aberration, contributing to the lens's high-resolution imaging capabilities.

The lens features a sophisticated geometry, with a thickness of 4.88mm at the edge, a center thickness of 3mm, and a center thickness 'a' of 2.5mm. The radii of curvature are R1 = 184.84mm, R2 = -134.06mm, and R3 = -393.98mm. The lens's design is a multiplet, which is a combination of multiple individual lenses to achieve specific optical properties.

The lens is coated with the EDM Vis-0 std curve on both the front and back surfaces. This coating enhances the lens's light transmission and reduces surface reflections, contributing to improved image quality and contrast.