Novel Optical Design of Large Aperture Supported Standard Wide Zoom Lens.

In this study, we designed a high-speed 16-50 mm F/1.8-2.8 zoom lens for advanced photo system type-C image sensors. Notably, this is the first attempt to implement a bright aperture of F/1.8 at the wide-angle end of a zoom lens. Compared to existing designs with fixed apertures of F/2.0-2.8 or F/2.8, our lens achieves a brighter open aperture while effectively suppressing aberrations and maintaining high resolution. Spherical aberration, chromatic aberration, and distortion are effectively controlled using three aspherical lenses and one extra-low dispersion lens. As a result, a modulation transfer function performance of over 80% at the center is achieved, even at F/1.8 in the wide-angle range. To enhance focusing performance, we adopted a second lens group with low aberration sensitivity as the autofocus driving group, contributing to reduced mechanical weight and improved stability. This design successfully realizes a high-speed zoom lens that delivers resolution comparable to or better than existing optical systems with brighter apertures, while also maintaining a well-balanced trade-off between optical performance and product size.