Generally, you will try several different versions at home to get a satisfactory shot. It is not difficult to understand why serious photographers use different lens tests and use them until they are satisfied. In order to balance different aberrations, a certain amount of residual aberration has to be preserved, and not every designer can think of the best solution.
In the assembly process of precision optical lenses, in order to achieve high precision and high efficiency and easy re-inspection, it is not only necessary to set up optical lens for high-precision instruments, but also to fully consider the needs of assembly in optical design and mechanical design.
This article uses two examples to explore the application of mechanical structure design in optical lens assembly:
Medium and low precision lenses are generally passive when assembled. Assembly accuracy is mainly determined by the machining accuracy of the inner wall of the lens barrel, and the contact between the lens and the lens barrel is generally "face" contact.
For high-precision lens assembly, active assembly must be used to monitor the relative position of the lenses during assembly to ensure their coaxiality and spacing. At this time, a certain gap and adjustment space are required between the lens and the lens barrel, and the assembly accuracy is no longer determined by the accuracy of the inner wall of the lens barrel. In order to ensure high precision and high sensitivity adjustment of the lens, the contact between the lens and the lens barrel support is generally "loop" contact, or a "narrow torus" contact specially designed for each lens radius.
In active assembly, if only the coaxiality is guaranteed, there are usually four degrees of freedom adjustment for the lens: 2D translation, 2D tilt. In actual lens design, lenses with different curvatures are sensitive to this adjustment, such as the greater the curvature, the more sensitive. From the perspective of efficiency and cost, in the design of the lens barrel, the support of the more sensitive lens is generally designed as a "loop" or "narrow torus" mode, while for a lens that is not sensitive, it is designed as a "face" contact support.