Handheld magnifiers, telescopes, and stand magnifiers are examples of which type of magnification?

Handheld magnifiers, telescopes, and stand magnifiers are examples of which type of magnification?

• A. Angular
• B. Relative distance
• C. Relative size
• D. Linear

Answer: (A)

Angular magnification is what these vision aids change. They make the image appear larger to the eye by increasing the angle that the image subtends at the eye, rather than by physically enlarging the object on a surface. A handheld or stand magnifier creates a virtual image at a convenient distance so the eye sees a much larger angle than without the lens, and a telescope increases the angular size of a distant object through the eyepiece, producing a bigger angle at the eye. If we spoke in terms of linear magnification, we’d be describing an actual increase in image size on a surface, which isn’t how these devices are used or defined. Relative distance magnification refers to perceived distance effects and isn’t the standard descriptor for these items. So the best way to characterize handheld magnifiers, telescopes, and stand magnifiers is angular magnification.

Angular magnification is what these vision aids change. They make the image appear larger to the eye by increasing the angle that the image subtends at the eye, rather than by physically enlarging the object on a surface. A handheld or stand magnifier creates a virtual image at a convenient distance so the eye sees a much larger angle than without the lens, and a telescope increases the angular size of a distant object through the eyepiece, producing a bigger angle at the eye. If we spoke in terms of linear magnification, we’d be describing an actual increase in image size on a surface, which isn’t how these devices are used or defined. Relative distance magnification refers to perceived distance effects and isn’t the standard descriptor for these items. So the best way to characterize handheld magnifiers, telescopes, and stand magnifiers is angular magnification.