Design of miniaturized two-steps 7.5^× zoom system in visible band

Many applications expect to search for targets with a large field of view (FOV) , and identify the targets in a relative small FOV. A miniaturized two-step 7.5^× zoom system was proposed and designed, which worked in the visible band of 486 nm~656 nm with a wide-angle FOV of ±15°, telephoto FOV of ±2°, F-number in both FOV of 2.8, and overall length of 60 mm. The system consisted of glass lenses and plastic-injection lenses, which contained one front fixed group and one movable group. The conversion of wide-angle search function and long-focus gaze function was completed by switching the movable group between two zoom positions, which had the advantages of miniaturization, lightweight and low cost.