The working principle of a magnifying glass is based on the focusing effect of a convex lens. When light passes through a convex lens, due to the different curvatures on both sides of the lens, the light refracts inside the lens, causing the light to converge towards the central axis of the lens. When we place an object within the focal length of a magnifying glass, the light emitted by the object refracts through the lens, forming a magnified virtual image on the other side of the lens. The size of this virtual image depends on the focal length of the magnifying glass and the distance from the object to the lens.

When using a magnifying glass, whether handheld or desktop, it is necessary to maintain stability in order to observe clear images. Therefore, it is important to avoid shaking or moving during use. Different magnifying glasses have different focal lengths, and the focal length needs to be adjusted according to the actual situation to achieve the best magnification effect.