A microscope’s axial zone of acceptable sharpness within the specimen is a critical performance parameter. It determines the thickness of a sample that can be simultaneously in focus. A larger value allows for imaging of thicker specimens without the need for refocusing, while a smaller one yields images where only a very thin section of the sample appears sharp.
Control over this parameter offers significant advantages in various applications. In materials science, it facilitates the examination of surface textures and irregularities. In biological imaging, it allows for the visualization of three-dimensional structures within cells and tissues. Historically, improving or manipulating this parameter has been a key objective in microscopy development, leading to advancements in lens design and illumination techniques.
