Paraxial imaging properties of double conjugate zoom lens system composed of three tunable-focus lenses

•Analysis of paraxial imaging properties of a double conjugate zoom lens composed of three tunable-focus lenses with a fixed position.•The distances between individual elements are fixed during the magnification or focal length change.•General formulas for the calculation of parameters of tunable-focus lenses are derived.•Derived formulas applicable for the initial design of zoom lenses with tunable-focus lenses.

Novel optical systems based on tunable-focus lenses represent emerging lens technology, which will enable to design optical systems with variable optical parameters with no analogy in conventional systems. Our work describes paraxial imaging properties and design parameters of a double conjugate zoom lens composed of three tunable-focus lenses with a fixed position. General formulas for the calculation of optical power of individual tunable-focus lenses are derived. The application of derived formulas is presented on three examples of optical systems for different imaging conditions.