focal length Definition

telephoto, zoom lens, aperture, viewfinder, lens, autofocus, chromatic aberration, megapixel, eyepiece, telephoto lens, diopter, fisheye, pentaprism, zoom, fisheye lens, aspheric, aspherical, spherical aberration, rangefinder, camera lens, defocus, collimator, monocular, tripod, magnifications, vignetting, pixels, iris diaphragm, leica, monopod, underexpose, brightness, parallax, confocal, arcsecond, flashgun, aspect ratio, transmittance, convex lens, diffraction, photometry, luminous flux, photodiodes, refractive index, emissivity, illuminance, passband, transmissive, absorption coefficient, isotropic, collimated, interocular, windage, diffractive, mosaicking, microampere, contrasty, fps, mydriatic, wavelength, picometer, imager, photometer, monochromator, optics, luminance, luminous intensity, photocurrent, circular polarization, capacitances, mju, obliquity, reticle, attosecond, femtosecond, photomultiplier, geoid, kev, refractor, micrometer, photodiode, interferometer, dipole moment, kinematic viscosity, image intensifier, etalon, potentiometer, variable resistor, unpolarized, gearset, formes, angstroms, magnetisation, detents, strain gauge, polarizer, inductance, millivolt, laparoscope, bypass capacitor,