line pairs per millimeter
Wavenumberexact by definition
Line pairs per millimetre is a spatial frequency of 10³ m⁻¹, and it is the standard measure of optical resolution. A lens's modulation transfer function is plotted against it, film and sensor resolving power is quoted in it, and a resolution target is a set of bar patterns at known lp/mm.
Watch out: A line pair is one dark bar plus one light bar, so a figure in lines per millimetre is twice the same figure in line pairs per millimetre. Sensor specifications sometimes quote the Nyquist limit in lp/mm, which is half the pixels per millimetre, and comparing a lens MTF figure against a raw pixel count without that factor of two overstates the system by a factor of two.
| 1 | 1,000 |
One line pairs per millimeter in every wavenumber unit
| 1,000,000 | per kilometer (km⁻¹) | |
| 1,000 | per meter (m⁻¹) | |
| 304.8 | per foot (ft⁻¹) | |
| 25.4 | per inch (in⁻¹) | |
| 10 | per centimeter (kayser) (cm⁻¹) | |
| 1 | per millimeter (mm⁻¹) | |
| 1 | line pairs per millimeter (lp/mm)this unit | |
| 0.001 | per micrometer (μm⁻¹) | |
| 0.000001 | per nanometer (nm⁻¹) | |
| 1.00000e-07 | per angstrom (Å⁻¹) |
Solvers that use wavenumber