Magnifier Lamp Buying Guide

This is not much of a guide to magnifying lamps, rather, more of some basic knowledge on the magnifying lenses. Whether to get a desk lamp type, a table/bench clamp type or a mobile stand type, is totally your choice depending on your application and budget. What we could do here is to assist you to find the appropriate lens. Right now we carry 3 (sometimes referred to as 3D or 3d, same for 5 diopter and so on) and 5 diopter lenses on many models, and 8 diopter lens on some other. Please understand that 3 diopter does not equal to 3X. There is a formula you can use if you really want to know how many Xs a lens is.

Where “D” is the diopter number given, and “X” being what we normally know as the power or strength of magnification. That is, use the given diopter numer, for instance, 3 to be divided by 4, then plus 1, that equals 1.75, which is what we call as the magnification strength, often expressed as 1.75X.

3D 5D 8D
Diameter 5″ / 127mm 5″ / 127mm 5″ / 127mm
Weight 0.71lb / 320g 0.93lb / 420g 1.28lb / 580g
Magnifying Strength 1.75X 2.25X 3X
Focus Range ≈ 1″ – 9″ ≈ 1″ – 7″ ≈ 1″ – 5″
Best Focus 7″ 5.5″ 3″
Readable Area Total Large Limited
View Distortion No Minor Severe

[Fig 1] 3 Diopter Lens

[Fig 2] 5 Diopter Lens

[Fig 3] 8 Diopter Lens

The lens is about 6″ above the viewed page. Please don’t get me wrong, it looks very clear when you are actually seeing through the lens, only that when we have to shrink the picture here to put it online, it doesn’t appear to be very clear as it should be. Please note that the viewed page looks almost the same everywhere in the lens.

The lens is about 5.5″ above the viewed page. If you compare the image that appears through this 5 diopter lens, with the image through the 3 diopter lens, you will see that the phone listings appear larger. Do you also notice that some distortion of the text begin to appear towards the edge of the lens? If you keep looking through the lens for rather long period of time, you might feel some discomfort. That is why we do not suggest to use a 5 diopter lens for reading purposes, unless your eye doc okays it.

The lens is about 4″ above the viewed page. Now, the image (magnified at the center of the lens) apparently appears larger than the other two pictures, of 3 and 5 diopter lens. It serves its purpose, doesn’t it? No sooner than the lens was placed on top of the page, when some listings went up smoke. (Another burn mark on the right side of the fingers, notice?) Very powerful. Unfortunately, you must also have noticed the readable portion of the viewed page becomes limited and the rest of the image towards the edge of the lens is so distorted that it eventually grows unreadable. Whatever your eye condition, this is definitely not recommended for reading purposes.

We hope the above information is helpful for you in choosing which lens is more appropriate for your application.