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Its aspheric optical design is matched to the conditions in which it is used. Image quality and distortion - with utilization of the highest possible magnification - have been optimized so that no aberrations of any consequence occur. The hand magnifier is labeled with its refracting power, which can be used to calculate the magnification on the basis of the condition of use.
Product dimensions (imperial): 6.75 inch H x 2.5 inch L x 0.75 inch W
Product dimensions (metric): 171.45 mm H x 63.50 mm L x 19.05 mm W
Features
• Magnifier has the largest possible diameter for its power
• Aspheric lens allows a clear view right up to its edge
• Lightweight lens is made of high-quality, unbreakable plastic
• Cardboard storage case is included
• Also includes tri-lingual user's guide in English, German and French
Principles of Magnification
Magnification products are an essential element in the daily activities of many individuals today. Whether the application is for commercial, professional or personal use, the magnifiers enhances one's ability to perform a task or enjoy a hobby. This information is to aid the professional or lay person in understanding how magnification works and how one can get the most out of the magnifier he or she is using. The principles of magnification apply to all magnifiers employing simple lenses or combination of lens.
Definitions:
Focal Length: The distance from the center of the lens (or lens system) to the viewed object. Working distance is the distance from the bottom of the lens, or the lens housing to the object when the object appears at maximum magnification without distortion. It is important to remember that as magnification increases, the focal length decreases.
Diopter (d): A term used to identify the refractive (light bending) capacity of a lens. In magnifiers, there is a direct correlation between focal length and diopter. To find the diopter of a magnification lens, follow these steps. With the eyes 10" above the lens, move the object to be viewed to the point the greatest distance below the lens where it remains in sharp focus. Measure this distance and divide into 1 meter (39.37"). The result is the diopter of the lens - e.g., if the object is at a 13" distance than it is a 3-diopter lens (39.37/13 = 3d). Each diopter increases the size of the viewed object by 1/4 (25%) when the object is at its full focal length from the lens.
Field of View: The distance across the lens surface to which the viewer brings both his eyes (note: eyes should be 10" above the lens). It is important to note that as magnification increases, meaning the lenses used are stronger, viewing areas and focal length decrease.
Magnification: The degree to which the viewed object is enlarged. Magnification is usually expressed by a number followed by an "x", the symbol used to express power or the size of the object in relationship to its actual size.
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Common Diopter/Power Relationships |
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Diopter |
Power |
% Bigger than object |
Focal Length |
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3 |
1.75X |
75% |
13" |
|
4 |
2.00X |
100% |
10" |
|
5 |
2.25X |
125% |
8" |
|
7 |
2.75X |
175% |
5.5" |
|
8 |
3.00X |
200% |
5" |
|
9 |
3.25X |
225% |
4.5" |
|
11 |
3.75X |
275% |
3.75" |
|
13 |
4.25X |
325% |
3" |
|
16 |
5.00X |
400% |
2.5" |
|
18 |
5.50X |
450% |
2.25" |
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20 |
6.00X |
500% |
2" |
If a dime was this small unmagnified - top...
3 diopter - 2nd dime 5 diopter - 3rd dime
10 diopter - 4th dime
15 diopter - largest dime
Selecting The Right Magnifier:
1. Determine the desired magnification for your needs. Remember, as you increase magnification, you decrease both the focal length and the viewing area.
2. Check to find out the correct diopter you need to achieve that magnification. The vast majority start with the standard 3 diopter lens and add secondary lenses or change primary lenses as needed.
3. Note the focal length and lens diameter that correspond to the magnification and lens diopter you have chosen, and make sure they are suitable for your task.
4. Select the primary and secondary lens combination required to achieve the desired magnification.
5. As a general rule, because the working distance will be less than 8", lenses or lens combinations above 5 diopter are recommended for inspection purposes only.
Tips on Proper use of a Magnifier:
To take best advantage of the comforts built into illuminated magnifiers, please keep these points in mind:
1. Use both eyes. Magnifiers are designed as "working tools". They can be used as comfortably as a pair of glasses.
2. Position the lens so that it is a proper distance from the work area, yet close enough for your eyes (8" to 10") so that you have the maximum magnification without distortion. Do not lean back away from the lens to increase magnification.
3. Chair height and work surface should be positioned so the operator can maintain good posture while working.
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