Improved Features -
Higher Sync Speeds, up to 1/320th (RF-602 were slow, RF-603 were very slow)
Locking Rings on trigger foot (RF-603 and flash on top would fall off the camera)
Pass Through Hotshoe now usable (see point above) though still manual only no TTL
Power Switch Finally Moved to the Side (was blocked by the flash on 602 & 603)
Compatible with non Canon/Nikon and single firing pin cameras (RF-603 was not)
Test Fire Button works off the camera hotshoe (for taking light meter readings) (RF-603 did not)
300v Safe Trigger Voltage (for hotshoe and PC sync port) (602/603 where low 12 volt safe limit)
- See more at:
YONGNUO RF-603 II – Now Available | FLASH HAVOC