Here's the response from Paul Buff. Doesn't really answer the question
but at least lets me know to ignore the manual with respect to max sync.
The link is to a video by David Ziser. I've known about the technique
but never tried it or seen it so thoroughly explained.
-----------------------------------------
Hey Chuck,
Thanks for contacting us! Sorry for the confusion! I believe we
wrote the manuals before we were able to test at such high speeds (in a
practical environment). Plus we specify this because even the camera
manufacturers specify this in their manuals as well. In the real world,
I have not heard of any of our customers, nor have I seen with my own,
any example of not reaching maximum sync. Also, since you use your bees
out doors, you may find this video of interest, and apologies if you
have seen it:
<http://strobist.blogspot.com/2008/10/great-video-on-overclocking-your-sync.html>
I hope this helps and clears up confusion, but if we can be of any
additional assistance, please let us know!
Thanks again,
David
Customer Service
Paul C. Buff, Inc.
White-lightning/Alienbees/Zeus
Check out our forum at:
http://www.paulcbuff.com/forums
--------------------------------------------
Chuck Norcutt
Chuck Norcutt wrote:
> The key here is your assumption about data rate. I don't know the
> answer. I've sent the following note to Paul Buff tech support. I'll
> post the response when I get it.
> ----------------------------------------
> In the Cybersync user's manual and in the frequently asked questions
> pages on your web site there are statements that the Cybersync has a
> 1/4000 sec. latency and can sync as fast as 1/2500 sec. Then the user's
> manual continues with a recommendation that, when using the Cybersyc,
> the camera's shutter speed should be set 1/3 to 2/3 stop slower than the
> camera's maximum sync speed. The specific example given is that a
> camera with a max sync speed of 1/250 second be set to 1/200 or 1/160.
>
> I don't understand "latency" here or sync as fast as 1/2500 followed by
> a recommendation to use less than 1/10th that speed. I understand that
> the camera in this case can't be set faster than its maximum x-sync
> speed of 1/250 but why does it need to be set even slower? More
> specifically, what does that mean for my Canon 5D with max sync speed of
> 1/200 second? Do I need to use 1/160 or slower? If the camera with
> 1/250 max sync speed can use 1/200 why can't I? An, once again, why
> can't the 1/250 camera use 1/250 if the Cybersync can sync at up to 1/2500?
>
> What don't I understand here? I do use my Bees outdoors for fill flash
> with large groups and every 1/3 stop is important.
>
> Thanks,
> Chuck Norcutt
> Endwell, NY
>
>
>
> Ken Norton wrote:
>> Chuck, I believe the latency numbers are calculated theoretical minimums.
>> Kinda like how Behringer calculates the specs for their audio products. ;/
>>
>> Just thinking off the top of my head:
>>
>> 1. Transmit rate is most likely no higher than 9600 baud.
>> 2. Datagram could be like four bytes or 32 bits.
>> 3. The entire datagram would take 1/300 of a second to transmit
>> 4. To achieve 1/4000 of a second, they could only be transmitting two
>> bits--not including ANY processing time.
>> 5. It is impossible to provide adequate channel assignment and protection
>> from falsing with only two bits.
>> 6. If one were to do this with ONE byte datagrams, at 9600 bps, it would
>> take 1/1200 of a second for transmittion of the datagram.
>> 7. These triggers are required to operate in the ISM (Industrial,
>> Scientific, Medical) bands. As such, there is plenty of other data
>> interference in the air on those same frequencies, so you'd need a larger
>> datagram to coexist with other wireless devices.
>>
>> To do this right with adequate falsing prevention, device control and
>> assignment, I can't imagine trying to do this with fewer than 8-bits.
>> Figuring a 50% overhead in detection and processing, it would take 1/800 of
>> a second before the trigger would fire. The next question is whether the
>> trigger itself is transister-based or relay based? Either way, you will
>> have a ramp-time delay.
>>
>> Now, consider that a strobe fires in a non-linear manner with the bulk of
>> the light emitted approximately 2/3 into the pulse. Consider the other
>> delays within the flash's electronics itself. I've found that using my
>> Minolta A1 as a test device when I fire strobes directly attached to the
>> camera that I get varying response rates with some flashes fully
>> illuminating the scene at 1/640 and others as low as 1/250. Monolites seem
>> to be worse than the Vivitars. At 1/250 everything works with the A1, but
>> if I'm using the ebay remotes, I need to back that off to 1/200 or less.
>>
>> Maybe Wayne can shed a little light in here on this subject, but I suspect
>> that any claims of 1/4000 response are a "bit" optimistic.
>>
>> AG
>>
>>
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