Christa Mrgan, for Macworld:
The use of Helvetica Ultralight as the system font is a mistake.
Especially at the small home screen size, yes. You’ll have noticed that most font sizes across the system are slightly larger. This is to compensate for the choice of the lighter Neue Helvetica weights,1 but it doesn’t quite work.
Despite the assurance of Mrgan and others, I’m certain it’s Neue Helvetica Light, not Ultralight, across most of the system. The clock on the lock screen is the only place that I can think of where the Ultralight weight is used. ↩︎