49-384 40 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=250mm VIS-NIR 400-1000nm

The 49-384 is a high-quality achromatic doublet lens, designed and manufactured by Edmund Optics. This lens, with a diameter of 40 mm, is specifically engineered for use in the visible (VIS) and near-infrared (NIR) spectrum, spanning 400-1000nm.

The lens features a focal length of 250mm, indicated by the EFL (Effective Focal Length) parameter. This long focal length makes it suitable for applications requiring a narrow field of view and high magnification.

The lens is constructed from two types of glass, N-BK7 and N-SF5, both from Schott. These materials are chosen for their excellent optical properties, including low dispersion and high transmittance in the specified wavelength range.

The geometry of the lens is carefully crafted, with a center thickness of 8mm and edge thickness of 10.57mm. The lens surfaces are coated with Edmund Optics' VIS-NIR coating (edm visnir0sp2002000), which enhances its transmission and reduces reflection, thereby improving overall light efficiency.

This lens is a multiplet, meaning it is composed of multiple elements. The curvature of these elements is precisely designed and manufactured to correct chromatic aberration, a common issue in lens systems where different wavelengths of light focus at different points. The curvature parameters (r1, r2, r3) are not explicitly provided, but they are integral to the lens's performance and are determined during the design and manufacturing process.