The optimisations within the optical design successfully maintain a high MTF profile over the entire image plane when exercising the broad 72:1 focal length change. A parallel optimisation paid close attention to minimising chromatic aberrations over this same focal range. Recognising the especially challenging nature of sports and event coverage (that regularly encounter challenging low scene lighting) the lens designers also gave a special priority to achievement of an impressive maximum relative aperture of f 1.7. Contrast was extended by superb control of black reproduction – with optical and mechanical design innovations that substantially reduced flare, veiling glare, and internal reflections. Similar attention to minimisation of ghost images and other highlight-related chromatic distortions caused by strong light sources on-axis and off-axis further extend the operational contrast range of the lens. The resulting superb contrast range of the lens augments its high picture sharpness. The combination ensures stunning picture clarity for sports, large events, and high-resolution surveillance imagery.