 This paper proposes a new method for calibrating a camera with varying focal lengths. It uses two images taken at different distances, and then uses the projection matrices to calculate the intrinsic parameters of the camera. These parameters are then used to calculate the optimal focus point for each image, allowing the camera to be calibrated accurately. This method has been tested on both synthetic and real data, and has shown good accuracy and reliability. This article was authored by Ismael El-Battoui, Abderahim Saidi, and Khalid Satori.