Design of optical system for 50^x zoom security lens

To meet the growing demands for high-performance zoom optical lenses in large-area surveillance and high-definition imaging within the security market, a smooth zoom optical system with a focal length range of 10mm to 500 mm was designed. The system employed a mechanical positive compensation method, where optimal initial structural parameters were determined through parameter setting and optimization. A moving aperture was implemented to maintain a constant F-number throughout the zoom range. Additionally, aspherical lenses were introduced to effectively correct positional and axial chromatic aberrations, thereby enhancing imaging performance. The optical system consists of 13 spherical lenses and 2 aspherical lenses, with a total length of 375.6 mm. The modulation transfer function (MTF) remains above 0.35 at 104 lp/mm across the entire zoom range. During the design process, motion curves for the zoom and compensation groups were plotted, demonstrating smooth, breakpoint-free transitions, which could validate the system's reliability and stability. Final analysis results indicate that the proposed system meets the practical large-area surveillance requirements and provides valuable references for the design of high-zoom-ratio optical systems.