放大率同为800×（倍）的显微镜，若由100×、N·A=1.30的物镜和8×的目镜组合，则不如由20×、N·A=0.95的物镜和40×的目镜组合更能看清样品的细节. Under the same magnification of 800 ×（Times), more details of the same sample can be observed by a microscope combined with the objective lens with 20 ×, N·A = 0.95 and an eyepiece of 40 × than a microscope combined with the objective lens of 100 ×, N·A = 1.30 and an eyepiece of 8×.