The phrase "extra sharpness" refers to having an increased level of clarity, focus, or intensity. It typically implies a higher degree of precision or accuracy in various situations. Full definition
In some photographs, that extra sharpness made a significant difference, especially in close - ups and when fine detail like text was photographed. (displaymate.com)
High carbon steel blade is heat treated for extra sharpness and long life. (medi-vet.com)
Sony also claims it helps to cut down on visible noise, while adding extra sharpness to images. (androidcentral.com)