Compound Microscope
A two-stage optical instrument utilizing a short-focal-length objective lens and a longer-focal-length eyepiece to achieve high magnification.
Governing formula
M_total = m_obj × M_eye ≈ (L / f_obj) × (D / f_eye)
SI unit
Dimensionless (×)
In depth
The objective lens forms a inverted real magnified intermediate image inside the tube, which the eyepiece then magnifies as a simple magnifier.
Examples in the real world
Biological laboratory microscopes achieving $400×$ or $1000×$ magnification to view cellular structures and bacteria.