Device for measuring relative aperture of photographic objective and measuring method thereof

Abstract

The invention discloses a device for measuring the relative aperture of a photographic objective. The device comprises an optical bench, a collimator, a diffusion screen, a holder, a camera assembly,a displacement table and a computer. The collimator is arranged on the optical bench, and the diffusion screen, a to-be-measured objective lens and the camera assembly are sequentially located in theoptical axis direction of the collimator; the diffusion screen is arranged on the optical bench through a fixing frame; a to-be-measured photographic objective lens is arranged on the clamp holder andis arranged on the optical bench through the clamp holder; and the camera shooting assembly is arranged on the displacement table, is arranged on the optical bench through the displacement table, andis connected with the computer. The invention further discloses a measuring method by using the photographic objective relative aperture measuring device. The measuring method comprises the followingsteps: assembling the device; measuring a focal length; measuring the entrance pupil diameter; deriving aperture values. By means of the mode, the entrance pupil diameter and the focal length can bemeasured, two kinds of equipment do not need to be used for measurement respectively, measurement steps are simplified, and the measurement accuracy can be improved.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to a measuring device for the relative aperture of a photographic objective lens and a measuring method thereof. Background technique [0002] Traditionally, the measurement of the relative aperture of the photographic objective lens is achieved by measuring its entrance pupil diameter and focal length respectively. [0003] For the measurement of the entrance pupil diameter, the focal plane point light source method is generally used for measurement or experimental measurement microscope measurement. In the traditional entrance pupil diameter measurement, the focal plane point light source method is used to measure the entrance pupil diameter of the photographic objective lens, and the size of the projected bright spot blocked by the frosted glass is equal to the entrance pupil diameter. In the measurement process, there will be errors due to the selection of frosted g...

AI Technical Summary

Problems solved by technology

[0005] The traditional measurement of the entrance pupil diameter of the photographic objective lens can only measure its focal length and entrance pupil diameter separately, measure two values, and then obtain its relative aperture value through calculation, which cannot achieve one measurement, and the operation steps are cumbersome, which easily leads to measurement Precision is not precise enough

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