Principles of Magnification
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As a rough and ready guide
- the larger the size of the magnifier, the lower the magnification.
- the higher the magnification, the smaller the field of view, as below.
It is generally easiest to use the magnifier that is the weakest that you can see with, as more words can be seen at one time, and reading is much easier.
With low magnification there is a large field of view, and many words can be seen at the same time. The lens tends to be larger.
With more magnification, fewer words can be be seen at once. The lens tends to be smaller. |
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Field of view with high and low power magnifying glasses
With most magnifiers the field of view, can be made wider …seeing more letters for instance…. by holding the object or book closer. This can make your arms or neck ache.
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If you hold things close to your face to read it can be awkward and tiring, especially if you need a magnifying glass, but more words come into view. |
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If you hold the magnifying glass further away it is often more comfortable, even if you see fewer words. |
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Good lighting
Reading with a good light helps. The light needs a reflector so the light shines on the book, not into your eyes. A strong light on the ceiling is not particularly helpful. A light with a reflector, angled on to the book is much more helpful.
The light needs to be positioned so that glare is reduced and shadows are minimal. If the magnifier is not internally illuminated lamp close to the table is usually better than a central light from the ceiling. This is like reading with day light behind you, but not very bright like sunlight. An anglepoise light is often essential for reading.