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How to Use a Hand Lens Magnifier
Usually when folks come in the store and want to
look at magnifiers, they begin looking at them by holding the
instrument out at arm's length.
 Actually
you get the best view of the subject by holding the lens as close to
your eye as possible and bringing the object up in front of the lens
until it is in focus (see picture). This might be a little bit
difficult to get used to if you have not done it this way before,
but with a little practice, you will find that you get absolutely
the best view of the subject.
A word about "focal distance." This is the
distance at which you must hold the subject in front of the lens for
it to be in focus. Notice in the photo here that the flower is
about an inch from the front of the hand lens. This is a 10x
hand lens. It magnifies 10 times, and one inch is the focal
distance. The higher the magnification, the shorter the focal
distance and the smaller the "field of view" or the area of the
subject that you will be able to view. So, with a 20x hand
lens (very difficult to use!), the focal distance is only 0.5 inch.
Keep this in mind when purchasing a lens. For most nature
study purposes such as tree identification, wildflower study, and
examination of insects and rocks, 10x is an excellent magnification. |
