New Large Size A4 3x Magnifier Fresnel Lens Full Page

A magnifying glass is a simple visual optical device used to observe small details of an object, and is a converging lens with a focal length much smaller than the visible distance of the eye. The size of the image of an object on the human retina is proportional to the angle (viewing angle) that the object faces the eye.
A magnifying glass, also known as a fire glass. A simple optical instrument that can obtain enlarged virtual images. Usually composed of a convex lens, frame, and handle. When using, place the object close behind the lens (within the focal length) to see an upright magnified virtual image, which helps to distinguish details. It is commonly used to view specimens, drawings, negatives, photos, movie copies, etc. Depending on the curvature and refractive index of the glass used, there are various options for amplification, such as 10, 20, and 30 times.
The larger the perspective, the larger the image, and the greater the ability to distinguish the details of objects. Moving closer to an object can increase the viewing angle, but is limited by the eye's ability to focus. Use a magnifying glass to place it close to the eyes and place the object within its focus, forming an upright virtual image. The function of a magnifying glass is to magnify the viewing angle. In history, it is said that the application of magnifying glasses was proposed by a bishop in 13th century England, Groeste.
As early as over a thousand years ago, people had ground transparent crystals or gemstones into "lenses" that could magnify images. Also known as convex lens.

• Magnification:3
• Condition:New
• Type:Magnifier
• Color:As Pictures
• Feature:Reading Magnifier
• Suitable:Universal
• Weight:0.1kg
• Place Of Original:Guangong China
• Shipping:Within 4 Working Days