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A Perfect Maginfier would have high
power, large area, light weight, high working
distance and crystal clear, distortionless magnification. But a perfect magnifier
incorporating all these properties is impossible as per the basic laws of physics.
You have to give up an advantage in order to gain another.
Therefore you should first decide which properties of magnifiers are more important for
you and which are less important and therefore can be sacrificed in favour of the more important
properties. And then by carefully going through the properties of the various magnifiers given
in this website select the one that best suits your requirements.
Given below is a brief description of the different properties of
magnifiers.
1. Magnification: Is the number of times an object will look bigger when viewed through the
magnifier. With increasing magnification you are able to see more and more fine details of the
object being magnified. But there will be corresponding decrease in all the other properties
mentioned below.
Your aim therefore should be to go for the lowest magnification that will
still enable you to see all the details you need to see in your given
application.
2. Field of View: Is the area or the size of the object that you will be able to see through the
magnifier. Field of view declines rapidly with increase in magnification.
3. Working Distance: Is the distance that has to be maintained between the
magnifier lens and the object being viewed in order to keep the object in
sharp focus. This is an important property if your work involves use of
tools on the object under magnification. For example to assemble watch
parts using a screw driver you will need adequate space between the
magnifier and the watch to operate the screw driver.
4. Quality of the image: The magnified view as seen through the magnifier should be bright,
sharp, without color fringes and without any distortion throughout the entire
field of view. Simple and relatively cheaper lenses can provide high image quality
at lower magnification but at higher magnifications one has to go for complex
multi-lens systems to get good quality image.
5. Depth of Field: Is the distance between the closest and the farthest point (on the object being
viewed) at which the magnifier remains in focus. For example if you are viewing an uneven
surface or a three dimensional solid object such as a rock sample, a magnifier with a small
depth of field will not be able to keep the entire object in focus at the same time.
6. Eye Relief: Is the maximum distance you can keep the magnifier from your eye and yet get
to see magnified image of the entire object. Larger eye relief provides greater viewing comfort
to the user. Hence you should go for larger eye relief if your application requires hours of
viewing through the magnifier. Like all the other properties mentioned above eye relief also
generally goes down as the power of magnifier goes up.
Mechanical configuration: Finally depending upon your requirement you should decide
between the following types:
* Whether the magnifier should be handheld or self standing or headband mounted or
spectacles mounted?
* Whether the stand should be flexible or rigid or foldable or transparent or opaque or
slotted type?
* Whether illumination is essential?
* Whether portability is essential?
* Whether the physical dimension and weight suit the nature of your application?
The respective mechanical configurations are explained in the product descriptions
given in this website. Carefully analyse your requirement then decide on the mechanical
configuration best suited for you as this aspect will have considerable bearing on the
usefulness of the magnifier for you.