Objective Numerical Aperture
(where n = refractive index, u = half objective acceptance angle) 
NA = n(sinu) 
Resolution  brighfield
(where λ = wavelength  0.55µm standard, NA_{o} =
objective NA, NA_{c} = condenser NA ) 

Resolution  darkfield
(where λ = wavelength  0.55µm standard, NA_{o} =
objective NA, NA_{c} = condenser NA ) 

Single lens magnification
(where f = focal length in mm) 

Objective magnification  finite tube length
(where OTL = optical tube length, f_{o}
 objective focal length) 

Objective magnification  infinity corrected
(where f_{∞} = focal length of standard
infinity tube lens, f_{o} = objective focal length) NB
Standard infinty tube lens focal lengths are Leica & Nikon = 200mm,
Olympus = 180mm, Zeiss = 160mm 

Eyepiece magnification (where f_{e}
= focal length of eyepiece in mm) 

Microscope magnification 
Mag = objective magnification x eyepiece
magnification 
Maximum useful visual magnification 
Mag_{max} =
1000 x NA 
Depth of focus (consider
wavelength λ = 0.55) 

Visual field of view (where FN
= eyepiece field of view number, Mag_{obj}
= objective magnification) 

Image intensity (for epifluorescence
substitute (NA)^{4 }) 
