Most fonts have one master design. — but the user never chooses them. Instead, iOS, macOS, and watchOS automatically deploy the correct optical size:
Technical analysis of the SF Pro Regular .ttf / .otf files reveals minor irregularities in the interpolation between Regular (Weight 400) and Medium (Weight 500). Specifically, the character ‘g’ (double-storey) shows a non-linear change in the descender loop width, creating a subtle ‘jump’ during variable font animation. This is likely an artifact of manual hinting rather than a design flaw, but it affects motion design. sf pro-regular font
: It features nine weights, ranging from Ultralight to Black, with "Regular" being the most common for body text. Detailed Analysis: SF Pro-Regular SF Pro has three