Does anyone know how or if high speed sync can be triggered using a Canon 7D and a Sigma EF-610 DG Super? After making all the settings as per the 610's manual, as soon as I meter/focus the camera defaults to 1/250 or slower shutter speed. Sigma claims it is the camera, but apparently the 7D is capable of FP or HSS with a dedicated Canon Speedlite. Thanks.
If the Sigma flash is compatible with the Canon HSS system then the settings should be accessible via the camera and should be set there rather than using the menu on the flash. Select: Menu-->Shooting 1(the first red tab)-->Flash Control-->External flash func. setting-->Shutter sync.-->Hi-Speed.
If any of the options along this path are grayed out or not visible, then the flash is not compatible with the HSS function of the 7D.
If you select the last ETTL setting (press mode button 6 times after switching the flash on) and then just press the
+ button twice, it enables high speed flash. You can make sure its on by checking your flash settings in the menu of your camera.