Paul C. Buff, Inc. Technical Forum

I recently purchased four E640's and am amazed at their performance. In conjunction with the E640s I purchased the CyberCommander and the associated receivers for the E640s. In my attempt to utilize HSS, I changed from the CC to the Flex TTL along with the Mini trigger.

I have noticed that when I shoot at 1/8000th of a second the only time I do not get banding is when the E640 is set to 640 ws. I am shooting with a Canon Mark IV. Is there a way to use the PW's with the E640 at that shutter speed with a lower WS setting?

Thanks
Mark

I am still getting familiar with the Hypersync/PW/Einstein usage. However, it has been my experience that full power is the best option to do this on Einstein. Hypersyncing differs from true HSS in that HSS pulses the light continuously to keep the same level of output throughout the exposure. Hypersync triggers the light early and then opens and closes the shutter during the burn time of the flash, using only one flash pulse. This works well for standard flash designs that have a longish flash duration. Einstein has its longest duration at full power, then rapidly shortens flash duration as the power is dialed down. Not far below max power, the flash duration of Einstein is less than the travel time of the first curtain's opening travel time. Thus, the first curtain is blocking the sensor rather than the second curtain which is the norm.

Did you change any of the hypersync settings?

You can try using color mode rather than action mode. This will lengthen your flash durations. However, if the shutter travel time (not shutter speed) is longer than the flash duration, part of your frame will be black. Shutter travel time is the time it takes the shutter curtain to move across the frame. This is constand regardless of shutter speed, and hovers around (or slightly faster than) the same speed as your x-sync. Shutter speed is the time between the first curtain and second curtain, and is independant of the travel time.

If it takes .004s for the curtain to travel and only .003s for the flash to completely fire and extinguish, there is still .001s worth of image not getting flash.

Full frame cameras will be at a disadvantage in that there is a longer distance to travel, thus takeing a longer amount of time. This may or may not be compensated for by using an upgraded shutter.