Paul C. Buff, Inc. Technical Forum

I was thinking;
Since High Speed Sync with dedicated flash is based on a strobing to extend the light duration while the shutter slit is crossing the sensor, would it be possible to program an E640 to strobe sufficiently to deliver higher shutter speeds at reduced power setting?
i.e. 1/500 at 300Ws or whatever?

I understand about the complexity of reverse engineering HSS for either Canon or Nikon, but a specific preset would be a nice option.

Considering that the E640 supports multi-frames per second with minimal light fall off because of the IGBT circuitry, it seems that the circuity would support the strobing required for the higher shutter speeds.

For example, if the shutter slit is 1/4 the sensor width, then 5 or 6 equally spaced flashes over the 1/500th of a second should result in a reasonable exposure.

It would be nice to have the early fire capabilities but that adds a component, the proprietary speedlite, to trick the camera into thinking it is doing HSS.

I am begininning to think in some of these directions, and Einstein can certainly do this sort of thing. But don't expect anything real soon - we are so overloaded in getting Einstein and improved PLMs in the hands of customers that I really have to allocate my time to the highest priorities first.

Glad to hear that's on the radar. There are situations where a long-duration flash can be really useful. If you ever get to exploiting all the capabilities, lots of interesting things should be possible. A series of pulses in increasing power might yield a faux rear-curtain effect, for example.

What would be nice and much easier is a straight multi-pop mode, like on a 580EX. For that matter, if Einstein can do 10fps at 50ws, I guess it could even be done externally. Optical slave off a 580 in Multi mode should work, shouldn't it? 10 pops/sec is usually plenty fast for me, but what's the limit to how fast Einstein can pop at low power?

Maybe some accessory geek could make a inline "strober" that takes one pulse and turns it into X pulses over Y seconds, set by the user. Or if they already do, I'd love to hear about it.

Multipops at 10fps are waaaaay to long to have any value for HHS. Fine for strobe effects. Don't hold your breath for this capability in Einstein . . . it would be a long development time.

Yeah, I was just thinking of strobe effects. Anyway, I can probably do it with an optical slave off a 580EX in Multi, I'd think... just have to stay within the Einstein working parameters.

Assuming I could trigger it somehow, what do you think are the most pops I could fire off, say, during the half-second between pitcher's mound and home plate? Think I could get 20? If so, would the power level be about 640/20=32ws?

Presuming that the shutter curtain travel is approximately the same speed as the sync speed, it would mean that the strobing would have to be kept up for 1/200 second. So, if the E640 could deliver 20 strobing pulses in that time it would require that each pulse is approximately 1/4000 of a second. The question becomes what would the effective Ws output be and how uniform the light would over that range. Or would it deplete the stored energy in the unit.

Einstein can do this, internally, fairly easily, but not externally via sync jack or transceiver. But to do it right the pulse width would have to be controlled over time so the light level is the same at the beginning and end of shutter travel. It's a big research project to get it right . . . done wrong you would also have a color balance issue from one end of the shutter travel to the end. So no quick answers from me today.

Having the Einstein essentially as a high powered HSS capable speedlight would make me jizz in my pants. :lol:

Add me to the list as another customer who'd love this feature.