Microscope Magnification
The total magnification of a compound microscope is the product of objective magnification (-L/f_o) and eyepiece magnification (D/f_e).
Variables
Derivation
The objective creates a real, inverted, magnified image at distance L from the objective. The eyepiece then acts as a magnifying glass on this intermediate image.
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- L = 2 m (Tube length (distance between lenses))
- fo = 3 m (Focal length of objective)
- D = 4 m (Near point distance (25 cm))
- fe = 5 m (Focal length of eyepiece)
Result: M = -0.53333333
Where this formula is listed
- Optics formulas, under Optical Instruments, alongside Numerical Aperture, F-Number (f-stop) and Depth of Field.
- In the optics list it comes after Magnifying Glass Magnification and before Telescope Magnification.
- Optics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Microscope Magnification formula?
Microscope Magnification is written M = −L/f_o · D/f_e. The total magnification of a compound microscope is the product of objective magnification (-L/f_o) and eyepiece magnification (D/f_e). It belongs to Optics, under Optical Instruments.
What are the units in M = −L/f_o · D/f_e?
In SI units, M is total magnification (dimensionless); L is tube length (distance between lenses), measured in m; f_o is focal length of objective, measured in m; f_e is focal length of eyepiece, measured in m; D is near point distance (25 cm), measured in m.
How is the Microscope Magnification formula derived?
The objective creates a real, inverted, magnified image at distance L from the objective. The eyepiece then acts as a magnifying glass on this intermediate image. The result is M = −L/f_o · D/f_e.