There are three requirements for outstanding lenses: refined design, precise manufacturing, and inspection, ensuring compliance with all specifications. SIGMA lenses are born of unique design concepts and superior manufacturing technology, but they are not complete until they undergo their uncompromising lens performance evaluation. SIGMA developed its A1 proprietary Modulation Transfer Function (MTF) measuring system using 46-megapixel Foveon direct image sensors. As a result, even previously undetectable high-frequency details are now within the scope of their quality control inspections. Every lens is checked before shipping. Thanks to ultra-high resolution sensors, high-performance shooting is assured.