magnification

Examples of magnification in the following topics:

• The Compound Microscope

  • The advantages of these microscopes, due to the multiple lenses, are the reduced chromatic aberrations and exchangeable objective lenses to adjust magnification.
  • Since each lens produces a magnification that multiplies the height of the image, the total magnification is a product of the individual magnifications.
  • where m is total magnification, mo is objective lens magnification, me is ocular lens magnification.
  • This diagram shows the setup of mirrors that allow for the magnification of images.

• Electron Microscopes

  • It has much higher magnification or resolving power than a normal light microscope.
  • It can achieve better than 50 pm resolution and magnifications of up to about 10,000,000 times , whereas ordinary, nonconfocal light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000 times.
  • This is why you can magnify targets to a much higher order of magnification using electrons rather than visible light.

• Combinations of Lenses

  • The magnification of such a telescope is given by
  • Note the sign convention: a telescope with two convex lenses (f1 > 0, f2 > 0) produces a negative magnification, indicating an inverted image.
  • A convex plus a concave lens (f1 > 0 >f2) produces a positive magnification and the image is upright.
  • The lens is more powerful for violet (V) than for red (R), producing images with different locations and magnifications.
  • The magnification can be found by dividing the focal length of the objective lens by the focal length of the eyepiece.

• The Thin Lens Equation and Magnification

  • We define the ratio of image height to object height (hi/ho) as the magnification m.
  • The magnification is related to do, di, ho, and hi by the following relation:

• The Magnifying Glass

  • The magnification of a magnifying glass depends upon where the instrument is placed between the user's eye and the object being viewed and upon the total distance between eye and object.
  • This type of glass would be sold as a 2x magnifier, but a typical observer would see about one to two times magnification depending on the lens position.

• Aberrations

  • Since the index of refraction of lenses depends on color or wavelength, images are produced at different places and with different magnifications for different colors. shows chromatic aberration for a single convex lens.
  • Another aberration or distortion is a barrel distortion where image magnification decreases with the distance from the optical axis.

• Shape

• The Camera

  • The focal length determines the magnification of the image, and the aperture controls the light intensity.

• Electric Activity in the Heart

  • High magnification micrograph of sinoatrial node tissue and an adjacent nerve fiber.