There are many optical instruments that magnify small or long-distance objects. They are used to make the image larger so that details are visible to the human eye. The magnification tools allow us to observe stars and planets, in order to distinguish their shape, colors and characteristics that would otherwise appear, to the naked eye, only luminous dots. An easy way to understand magnification is to think about what an object would look like if it were larger than a certain number of times. This 'number of times' is called the magnifying power of the optical instrument. A magnifying tool involves the use of one or two lenses. Read on to learn how to calculate its power.
Steps
Method 1 of 2: Single Lens Magnification Tools
Step 1. Determine the magnification
This value (M) corresponds to the focal length of the lens (FI) divided by itself minus the distance of the object from the lens (FI-D). The magnification equation corresponds to M = Fl / (Fl-D). Consult the instruction manual of the manufacturer of the instrument to know the focal length of the lens or you can read it directly on the lens (it is expressed in millimeters).
Method 2 of 2: Two Lens Magnification Tools
Step 1. Identify the two lenses that make up the instrument
The one that is positioned closest to the eye is called the ocular. The one closest to the object is called the target.
Step 2. Determine the focal length of the lenses
Consult the instrument manual to find the focal length of the lens (FIO) and that of the eyepiece (FIE).
Divide FlO by FlE. The result is the total magnification power of the instrument
Advice
- The magnification of the binoculars is expressed as a number multiplied by another. For example you can find models that are described as '8x25' or '8x40'. When you find this expression, know that the first number indicates the magnification of the binoculars, so '8x25' and '8x40' indicate two instruments with the same magnification power (8). The second number refers to the diameter of the objective lens and therefore the amount of incoming light.
- Remember that for single-lens instruments, the magnification is a negative value if the distance between the object and the lens is greater than the focal length of the lens. However, this does not mean that the object appears shrunken, only that it will be displayed upside down.
