And here's the next question and answer.
---------------------------------------------
Hey Chuck,
The reason it is ever brought up, by us or others, is if the sync speed
is right on the threshold, then some devices may introduce a lag or
latency, therefore effectively lowering your sync speed. The 1/3 to 1
stop variation we and other manufacturers include is more of a buffer
zone, that way if there is one anomaly, we can't get blamed for false
advertising. I hope this helps explain it a little more clearly. If we
can be of any further 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
-----Original Message-----
From: Chuck Norcutt [mailto:chucknorcutt@xxxxxxxxxxxxxxxx]
Sent: Friday, October 31, 2008 3:59 PM
To: info at Paul C Buff.com
Subject: Re: Cybersync x-sync question
That doesn't really explain what I asked but at least I know to ignore
the manual on max sync speed.
Thanks,
Chuck Norcutt
--------------------------------------------
Chuck Norcutt wrote:
> 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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