DETERMINING THE DISTANCE WITH STADIAMETRIC THREAD RANGEFINDERS WITH ZOOM LENSES

Abstract

The influence of the angular increase of the zoom-afocal system of the zoom zoom lens on the shift of its front focus, the position of which determines the exact value of the measured distance, is studied. Two variants of the zoom-afocal system are considered. The first version of the two components contains two fixed vario lenses. The second option has four lens components, of which the first and fourth are fixed, the second and third are movable.For an afocal system consisting of two components, an analytical expression is found for a segment that indicates the position of the front focus of the zoom lens depending on the angular magnification of this system. For an afocal system consisting of four components, a method has been developed and presented for calculating the position of the front focus of a zoom lens, which depends on the angular magnification of the afocal system.The exact formulas for calculating the range determined by the indicated rangefinders are given.Graphs and calculations showing the shift of the front focus of the zoom are given. It is shown that the shift of the front focus is significant. This shift must be taken into account when determining the exact distance to the measurement object.