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Optics
Optics

Microscope Magnification

M=−Lfo⋅DfeM = -\frac{L}{f_o} \cdot \frac{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).

Variables

M
Total magnification
unitless
L
Tube length (distance between lenses)
m
f_o
Focal length of objective
m
f_e
Focal length of eyepiece
m
D
Near point distance (25 cm)
m

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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Common questions

What is the Microscope Magnification formula?

Microscope Magnification is written M = -L/fₒ ·D/fₑ. 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/fₒ ·D/fₑ?

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/fₒ ·D/fₑ.