The invention relates to a
medium wave infrared continuous zooming optical
system with high
zoom ratio, belongs to the technical field of
optic lens, and aims to solve the existent problems of long zooming
stroke, large F value and more lens in the prior art. The
system comprises a front fixing group, a lens A of a time changing group, a lens C of a compensation group, a lens B of the time changing group, a lens D of the compensation group, a back fixing group, a secondary
image formation group and a probe, coaxially arranged from left to right in sequence, wherein the continuous zooming of the
system is realized through the axial movement of the time changing group and the compensation group. Through adopting the structure that the lens A and the lens B of the time changing group and the lens C and the lens D of the compensation group are arranged in a crossing manner to move, the continuous zooming is realized, the zooming
stroke is short, the curve is smooth, 100% cold light stop efficiency is satisfied, the F value is constant to be 2, the continuous zooming can be carried out within the range of 10 mm to 300 mm of focal distance, and the
image formation quality is sound in the whole focal distance range.