Correcting for these aberrations is what drives up the cost of inspection systems. Test Drive a Microscope Designers can organize the components of an optical system in only a few ways to obtain high-magnification microscope optics. They face additional limitations because even those few components can distort images. These distortions, which limit image quality, arise from optical flaws, or aberrations.
Every optical instrument suffers from aberrations to some extent.
This information on optics will help you when it comes time to purchase a microscope and you need to judge the quality of the instrument's optics. Figure 1 shows a simple lens focusing a collimated beam of light at a point. A real, simple lens wouldn't focus all the rays at the same point. Various rays passing through the lens would miss the focal point by different amounts, depending on how the shape of the lens differs from an ideal lens shape. Optical engineers call the ideal lens shown in Figure 1 the first-order approximation.