49-287 50 mm Dia. N-BAK4/N-SF10 Achromatic Doublet; EFL=250mm VIS 0° 425-675nm

The 49-287 is a high-quality achromatic doublet lens, boasting a 50 mm diameter and an effective focal length (EFL) of 250 mm, specifically designed for the visible light spectrum ranging from 425 to 675 nm. This lens is sourced from the reputable optical vendor, Edmund Optics, and is available for purchase through their website.

The lens is constructed from two types of Schott glass: N-BAK4 and N-SF10. These materials are carefully selected to minimize chromatic aberration, a common issue in optical systems where different wavelengths of light are focused at different points. By combining these materials, the 49-287 achieves superior image quality and color correction.

The lens geometry is meticulously designed, with an inner radius of 0 mm, an outer radius of 0 mm, and a center thickness of 9.75 mm. The edge thickness measures 10.54 mm, while the central thickness near the aperture is 3.5 mm. The lens's base shape is circular, and it features a standard antireflective coating on both the front and back surfaces, further enhancing its performance.

This lens is classified as a multiplet, indicating that it is composed of multiple elements. The curvature of the lens surfaces is defined by the radii r1 (-162.59 mm), r2 (123.82 mm), and r3 (-402.58 mm). These precise specifications contribute to the lens's excellent optical performance.