What are the different types of optical systems used in optical comparators? There are there main types of optical systems used in optical comparators: simple optics, corrected optics, and fully corrected optics. The simple optics system uses only a source of light, a lens for magnification, a mirror for reflection, and a projection screen. Simple optics will display an image that is reversed and upside-down. The corrected optics system adds to the simple optics system another internal mirror such that the image it produces is actually right-side-up and reversed. Finally, a fully corrected optical system creates a final projected image of the part that is both right-side-up and unreversed. Any of these systems can be sufficient to complete a measurement on an optical comparator, but the more advanced a system you use the less work there will be when converting the taken measurement back to the corresponding measurement of the part.