Ihagee and Plaubel
13 and 13 researched events on one shared scale. Ihagee 1912–present, Plaubel 1902–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.
Ihagee1912–present · 13 events · 4 concurrent threads
Plaubel1902–present · 13 events · 3 concurrent threads
1 span collapsed, 6 years in total, where neither maker has a research point: 1903–1908. Collapsing keeps a short-lived maker readable beside a long-lived one; the years are removed from the drawing, never from the record.