What is the relationship between diopter and magnification of a magnifying lens?

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E-Tay What is the relationship between diopter and magnification of a magnifying lens? Introduction

E-TAY INDUSTRIAL CO., LTD. is Taiwan supplier and manufacturer in Optical Industry. E-Tay has been offering our customers high quality Magnifying Glass, Magnifying Sheet, Headband Magnifier, Lighted Magnifier, Page Magnifier since 1980. With both advanced technology and 38 years experience, E-Tay always make sure to meet each customer's demand.

What is the relationship between diopter and magnification of a magnifying lens?

Diopter refers to the curvature of the lens. As the diopter increases, the lens become 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. Powers refers to how much larger an object is made to look through a magnifying lens. Power is typically indicated by an X such 2X or 4X. There is more than one formula to converts the diopter of a lens into its power, we as a company use the common formula: Magnification = (Diopter / 4) +1

For example an 3 diopter lens makes an object look 75% times larger, over and above what the unaided eye already sees.
As you increase the magnification the lens size effectively decreases. It is not possible to get a high power lens in a large diameter. Opticical combinations are a compromise for the “ideal” magnifier.

We have tabulated a guide for magnification levels,as compared to Diopter:2Diopter=1.50x Mag 3 Diopter = 1.75x Mag 4 Diopter = 2.00x Mag 5 Diopter = 2.25x Mag 7 Diopter = 2.75x Mag 8 Diopter = 3.00x Mag 9 DIOPTER = 3.25x Mag 11 Diopter = 3.75x Mag 13 Diopter = 4.25x Mag 16 Diopter = 5.00x Mag 18 Diopter = 5.50x Mag 20 Diopter = 6.00x MAG

Chart of the relationship between diopter and magnification

Here is an example, if a lens has diopter +3, its focal length is 3/4 + 1=1.75, and a lens of +4 diopter has focal length 4/4 + 1 = 2. By this way, you can easily calculate the magnification power of a lens from its diopter.

3X Rectangular Handheld Magnifier

8 Diopter = 3.00x Mag

3x rectangular handheld magnifier

2X Bar Magnifier with Color Guiding Line for Reading

4 Diopter = 2.00x Mag

2X Bar Magnifier with Color Guiding Line for Reading

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