Variations in magnification from the center to the edge of an image, making straight lines seem to curve. Barrel, or negative, distortion causes a square grid to appear barrel shaped; pincushion, or positive, distortion increases in proportion to the distance from the center of the image.
SPHERICAL VS. ASPHERIC LENSES
HOW THEY’RE USED IN IMAGING APPLICATIONS
Optical Lenses are often categorized by their shape. Two common surface shapes are spherical and aspherical. Each offers unique characteristics that make it suitable for different use cases.