How to Choose a Lighted Magnifier
A lighted magnifier, or illuminated magnifier, is an essential tool for anyone involved in precision assembly or design, but it is also an excellent aid for people who have troubled vision. Lighted magnifiers reduce eye strain and fatigue while allowing the user to see the small details of the object being viewed.
What diopter lens should you choose?
Diopter refers to the curvature of a lens. As the diopter increases, the lens becomes thicker and the curvature greater. As the curvature increases, light rays are redirected to fill a greater portion of the viewer’s retina, which makes the object look bigger. The higher the diopter, the more magnification the lens provides.
How do diopters translate to power?
Power refers to how much larger an object is made to look through a magnifying lens. The relationship between diopters and power is: diopters divided by 4 + 1 (original object) equal power. For example, a 16 diopter lens would be (16 diopters ÷ 4 + 1 = 5X power).
Why is focal length important?
Focal length is the distance from the center of a lens to the point where the light rays converge and the object is in optimal focus (focal point). This is also known as the “working distance” of the lens. Focal length is important when the task requires using tools with the object being viewed. Because focal length decreases as power increases, there is less room to perform work on an object under higher power lenses.
How big will the field of view be?
The field of view is the size of the magnified area under the lens that is in focus. The field of view decreases as power increases. More powerful lenses make small details look big, but less of the total object is visible. There is a trade-off for the viewer who must decide between the size of the field of view and amount of magnification.