Synchronisation.

EN: Synchronisation.

Fotografie

Concerted action of shutter opening and closing of electrical contacts to fire aflashbulb or electronic flash at the correct moment to make most effficient use ofthe light output. Roughly speaking, FP or M-synchronisation is constructed to fireflashbulbs just before the shutter is fully open, allowing a build-up time, and X-synchronisationfires electronic flash exactly at the moment the shutter is fully open.
Mir glossary