The 47-657 is a high-quality achromatic doublet lens, sourced from Edmund Optics, featuring a 9 mm diameter and an effective focal length (EFL) of 45 mm. This lens is specifically designed for use within the visible light spectrum, spanning 425-675 nm.
The lens is constructed from two distinct materials: N-BK7 and N-SF5, both from Schott. This combination is strategically chosen 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 47-657 achieves superior color correction, making it ideal for a wide range of applications.
The lens geometry is meticulously designed, with a thickness at the edge of 3.76 mm and a center thickness of 3 mm. The inner and outer radii are 0, and the lens features a first radius (r1) of 27.83 mm and a second radius (r2) of -19.75 mm. The third radius (r3) is -57.06 mm. These specifications contribute to the lens's overall performance and optical quality.
The 47-657 is coated with EDM VIS-0 std curve on both the front and back surfaces. This coating enhances the lens's durability and optical performance by reducing surface reflections and increasing transmission.