Hasselblad and Voigtländer
11 and 8 researched events on one shared scale. Hasselblad 1841–present, Voigtländer 1756–present.
The axis stretches where either maker has research and collapses where neither does, so a year sits opposite the same year on both. Event counts differ because research depth differs, not because one company did less.
Hasselblad1841–present · 11 events · 2 concurrent threads
Voigtländer1756–present · 8 events · 2 concurrent threads
Read either maker on its own: Hasselblad · Voigtländer