45-216 25 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=400mm MgF2 400-700nm

The 45-216 is a high-quality achromatic doublet lens, designed and manufactured by Edmund Optics. This lens, with a diameter of 25 mm, is specifically engineered for use in the 400-700nm wavelength range, making it suitable for a wide range of optical applications.

The lens is constructed from two types of glass, N-BK7 and N-SF5, both from Schott. This combination is used to correct chromatic aberrations, ensuring that the lens produces sharp, clear images. The lens has an effective focal length (EFL) of 400mm, providing a long focal length that can be used for high magnification applications.

The lens features a MgF2 coating on both the front and back surfaces. This coating is standard for Edmund Optics and provides a high transmission rate in the visible spectrum, reducing reflections and improving light transmission. The coating is also designed to provide a standard curve, ensuring consistent performance across different lenses.

The lens geometry is also carefully designed. The edge thickness is 5.03mm, providing structural integrity to the lens. The inner and outer radii are both zero, indicating that the lens is a simple doublet. The center thickness is 3mm, with a slightly reduced thickness of 2.5mm at the center a. This geometry is designed to provide the optimal balance between optical performance and physical durability.