Total Magnification Calculator
Objective magnification f_TL/f_obj, camera magnification with a C-mount adapter, visual magnification with an eyepiece, and the useful range 500–1000 × NA.
Results
Visual magnification within the useful range.
Magnification vs objective focal length
Model
M_obj = f_TL / f_obj; M_camera = M_obj · M_adapter; M_visual = M_obj · M_eyepiece
Useful visual magnification 500·NA to 1000·NA; exit pupil 500 mm · NA / M_visual
Infinity-corrected microscope: the tube lens forms the intermediate image. A C-mount camera adapter is a relay with its own magnification (0.35×, 0.5×, 0.63×, 1×), independent of the tube lens. An objective's marked magnification assumes its maker's tube lens (Nikon and Leica 200 mm, Olympus 180 mm, Zeiss 164.5 mm), so its focal length is that length divided by the marking; behind another tube lens it scales with f_TL. Eyepiece power refers to a 250 mm viewing distance. In the useful range the exit pupil is 0.5–1 mm.
Model and references
Textbook approximation. A standard approximation from the literature (for example paraxial, plane-wave or Gaussian-beam), valid within the range the page states. About the tiers
Infinity-corrected microscope. The camera adapter is a relay with its own magnification; eyepiece power refers to a 250 mm viewing distance. The useful range 500–1000 × NA is a rule of thumb for the eye.
- Greivenkamp J. E. (2004). Field Guide to Geometrical Optics. SPIE Press. Microscopes: objective magnification and eyepiece power 250 mm/f. doi:10.1117/3.547461
- Nikon MicroscopyU. Useful Magnification Range. Useful total magnification 500 to 1000 × NA. microscopyu.com