The second version also has wider and deeper knurling on the focusingring than the previous version.
第二版调焦环上的棱比前一版更宽更深。
2
With the structure, the focusingring can be quickly clamped on the optical mode lens; and assembly and disassembly are convenient and positioning is accurate.
由于本实用新型采用了上述结构，调焦环可快速地卡装在光模镜头上，拆装方便、定位准确。
3
We investigate the dependence of the focusing contribution on the order m of local ring of underlying traditional Fresnel zone plate.