The Viltrox AF 40mm f/2.5 STM ushers in a new dimension of full-frame versatility with a unique "normal" focal length, strategically positioned between 35mm and 50mm to offer a perspective close to that of the human eye, ideal for documentary reportage and environmental portraits. This lens embodies the Air series philosophy, combining an ultra-lightweight and manageable design (approximately 167 grams) with advanced optical performance. The internal construction, featuring 10 elements in 6 groups, integrates one Extra-low Dispersion (ED) lens, one Aspherical element, and three High Refractive (HR) elements, effectively minimizing aberrations while ensuring excellent sharpness and high contrast right from the maximum f/2.5 aperture. The Internal Focus (IF) system is driven by a fast and silent Stepping Motor (STM), optimized for subject tracking in both photo and video modes, with an emphasis on suppressing focus breathing. Equipped with a durable metal alloy mount featuring a USB-C port for firmware updates, this 40mm is the ultimate solution for photographers and videographers who demand compactness, pleasing bokeh at wide aperture, and maximum operational responsiveness.