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A hands free magnifier lamp is often
the best all purpose solution. These come in many shapes and sizes;
strengths and prices. The biggest, the most powerful, the most
expensive, are not necessarily the best options for everyone. But
choosing the right magnification for your needs can be confusing.
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Without being too technical, I
thought a brief overview and clarification of the main terms used might
be a helpful guide. Some ads rate magnifier lamps in Dioptres, some in
power, some in %, some in X. So what do they all mean; well the first
thing to understand is that if a lamp is described as 3 Dioptres, it
does NOT mean that it magnifies 3 times (3X) - (see chart below)
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Dioptre: is a unit of the optical
power of a lens equal to the reciprocal of the focal length measured in
metres. Or put simply, it refers to the curvature of the lens. As the
curvature increases, the lens becomes thicker, the Dioptre increases and
provides higher magnification.
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Power: refers to how much larger an
object appears, typically expressed as X eg: 2x or 4x etc. Dividing
Dioptres by 4 gives the Power of a lens eg: 3 Dioptre is 0.75x or 75%
increase
in size.
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Magnification: another way of
expressing the power but includes the original as 1 or 100%. Dividing
the Dioptres by 4 and adding 1 gives the magnification, eg: 3 Dioptre is
1.75x or 175% of the original.
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Focal
length: basically this is the
working distance between the object and the lens. The higher the
magnification, the nearer the object needs to be to the lens.
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Lighting: good quality lighting,
correctly positioned, is essential for any close work. Magnifier Lamps
of course have integral lights shining onto the object away from
your eyes. If accurate colour definition is important, standard warm
white bulbs or tubes (rated at 2700Kelvin) have a yellowy tint and will
distort colours. A cleaner, more neutral shade is more suitable, from
cool white (4000k) to daylight (6400k). Even if you don't need true colour
definition, cool white will give a cleaner light and reduce
eye strain; daylight is even better but usually more expensive.
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General: to avoid eye strain or a
stiff neck when using a magnifier lamp, arrange your chair, table and
the lamp in a convenient and comfortable position. Use both eyes which
should be about 8-10 inches from the lens, then move the object closer
or further from the lens until the image is clear. Wear spectacles if
you normally do.
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Tips: when choosing a magnifier
lamp, bear in mind that the more you magnify an object, the less of it
you will see.
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Finally: consider carefully the
specification to make sure the magnifier lamp you are buying suits your
needs. If full details are not given, ASK. Here at UKR Design, we
welcome questions from customers as we like you to know exactly what you
are buying - and from our point of view it avoids returns - so we are
all happy.
