A zoom lens is a lens with adjustable magnification. The most important feature of zoom lenses is their ability to continuously and infinitely adjust the magnification within a certain range without changing the working distance during the zoom process, which makes them ideal for industrial applications that require dynamic observation and precise measurements.

For example, the 4K zoom industrial lenses from POMEAS offer a large field of view, high resolution and continuous zoom capability, making them particularly suitable for high-speed inspection and precise measurement, such as in the semiconductor inspection and measurement industry.

The eyepiece, also known as the catch-eye, is the part of the microscope that is used to further magnify the image produced by the objective lens so that the human eye can see the details. Eyepieces usually have a fixed magnification and are used in conjunction with the objective lens to obtain total magnification. Eyepieces can be simple in design or more advanced, such as Periplan eyepieces, which provide better correction and flat field performance .

The objective lens, on the other hand, is the lens that is in direct contact or proximity to the sample being observed and is responsible for collecting light from the sample and forming the first image. Objective lenses range in magnification from low to high, and their numerical aperture (NA) is a key parameter in determining resolution and image brightness. Objective lens designs can be achromatic, flat-field achromatic, semi-complex achromatic, or complex achromatic, each corrected for specific optical aberrations .

These three components can be distinguished on the basis of whether their magnification is adjustable (zoom lenses are adjustable, eyepieces and objectives are usually not), their position in the imaging system (eyepieces are close to the observer's eye, objectives are close to the sample), and their effect on image quality (objectives affect resolution and brightness, eyepieces affect field of view size). These characteristics allow us to clearly distinguish between zoom lenses, eyepieces and objectives, and to select the right optical components for specific industrial inspection needs.