Magnifying power v/s magnification

[thebiggerbang]

Why is it that we prefer to use magnifying power instead of magnification for optical instruments like microscopes and telescopes?

 

[chrisbaird]

I believe "magnification" refers grammatically to the object being imaged. To say that a microscope has a magnification of 10 times would technically imply that we have a picture of the microscope zoomed up. To describe the tool doing the magnifying instead of the image, we then need a different term, such as magnifying power.

 

[Drakkith]

From wikipedia on magnification:

Magnification is the process of enlarging something only in appearance, not in physical size. This enlargement is quantified by a calculated number also called "magnification". When this number is less than one it refers to a reduction in size, sometimes called "minification" or "de-magnification".

and magnifying glass:

The magnification of a magnifying glass depends upon where it is placed between the user's eye and the object being viewed, and the total distance between them. The magnifying power is equivalent to angular magnification (this should not be confused with optical power, which is a different quantity) The magnifying power is the ratio of the sizes of the images formed on the user's retina with and without the lens

It looks like Magnification is the PROCESS of magnifying something, while magnifying power is a way to measure the magnification.

 

[RedX]

Because technically when your object is at the focus of a lens, the magnification is infinite, but the image is infinitely far away, so what's important is the angular magnification or what's in the parlance, magnifying power, which is the ratio of the angular size of the object with the lens divided by the angular size of the object placed 25 cm in front of the unaided eye (this is the largest you'll see the object in focus).

In equations, magnification is [itex]m=\frac{y_i}{y_o}=\frac{x_i}{x_o} [/itex], while magnifying power is [itex]MP=\frac{\alpha_i}{\alpha_o}=-25(\frac{1}{x_i}-\frac{1}{f}) [/itex] where subscript i stands for image, subscript o stands for object, y is the height, x is the distance to the lens, f is the focal point, and alpha is the angle with respect to the axis of lens.

 

[sardar]

Magnifying power and magnification are two terms that are often used interchangeably, but they actually have different meanings. Magnifying power refers to the ability of an optical instrument, such as a microscope or telescope, to increase the size of an object being observed. It is typically expressed as a numerical value, such as 10x, 20x, etc. On the other hand, magnification refers to the ratio of the size of the image produced by the instrument to the actual size of the object being observed. It is expressed as a unitless value, such as 10:1, 20:1, etc.

The reason we prefer to use magnifying power instead of magnification for optical instruments is because it provides a more practical and meaningful measure of the instrument's capabilities. Magnifying power directly tells us how much larger the object will appear when viewed through the instrument, whereas magnification does not provide any information about the actual size of the object.

Additionally, magnifying power is a more useful measure when comparing different instruments. For example, if one microscope has a magnifying power of 10x and another has a magnifying power of 20x, we can easily determine that the second microscope will provide a larger image of the object. However, if we were to compare the same microscopes based on magnification, with one having a magnification of 10:1 and the other having a magnification of 20:1, it would not be immediately clear which instrument would provide a larger image.

In summary, magnifying power is a more practical and meaningful measure of an optical instrument's capabilities compared to magnification. It is easier to understand and compare between instruments, making it the preferred term for describing the magnifying abilities of microscopes and telescopes.