VARIABLE FOCUS LENS, OPTICAL DEVICE, AND ZOOM LENS MANUFACTURING METHOD Russian patent published in 2017 - IPC G02B15/16 G02B15/173 

FIELD: photography.

SUBSTANCE: variable focus lens comprises, in order from object, first lens group, having positive refractive force; second lens group, having negative refractive force; third lens group, having positive refractive force; and fourth lens group, having positive refractive force. Following relationships are satisfied: 1,90<(-f2)/fw<3.00 and 0.05<f1/ft<0.50, where f2 is second lens group focal distance; fw is variable focus lens focal distance in wide-angle lens final state; f1 is first lens group focal distance; ft is variable focus lens focal distance in telescopic lens final state.

EFFECT: technical result is providing variable focus lens and optical device with good image quality and high scaling coefficient.

21 cl, 28 dwg, 4 tbl