I just bought a crown graphic with a Graphex Optar 135/4.7 in a Graphex Full Syncromatic shutter and a vivitar 285. The flash seems to work fine up to 1/50 but it only work about 20% of the time over 1/50 shutter speed. Is the 1/50 speed the fastest that this shutter will sync with the flash or is there a possible internal problem. Any help is greatly appreicated.

The shutter should synch at all speeds. Because of the shorter duration of contact closure above 1/50th, failure to trigger the flash could be corroded contacts. Fred.