Stopping motion with studio strobes and MFDB

[Snook]

Frank I cannot say much about Elinchroms , But they must be the ONLY ones that work that way.
you MUST have the Packs on LOWEST setting to get the SHORTEST flash duration on MOST ANY PACKS... Period!
So what your saying is just the OPPOSITE of the norm!
I sometimes use fast (1/6600) Elinchroms and they are indeed fastest at the full power (indeed, full power means 250Ws for the monoblocs called "250R").
At least that's in specifications and the results in the real world seems to confirm that.
Also the A3000N heads give a pretty fast speed (1/2000 aprox) on the AS generators.
And also Hensel has a breed of pack/heads combination (I can't recall the names) capable of 1/7500, also at full power (1500Ws with all the 3 heads at a time, meaning 500ws per head).

They are the OPPOSITE of the norm because all use a different "scheme" of... well, downshifting, being designed mainly for short flash duration at full power.
The drawback is that all of these fast strobes are also shorter on life expectancy...

HTH
[a href=\"index.php?act=findpost&pid=157691\"][{POST_SNAPBACK}][/a]

Now that was an explanation...
Thanks a lot and I agree with you...
Not sure what hensel you thinking of because I looked into them a lot when I was on the quest for Short Duration flashes..  
In the Specs the Elinchroms are always way up there in the Short Duration...
Was going to buy some from B&H but they never have them in 240V? And went with another Brand..
Snook
Snook

[Graham Mitchell]

The reason flashes are shorter at lower power is because the flash tube is designed to operate at a specific brightness and colour temperature. The duration of the flash is the way in which the total light output is controlled.

Sorry but I can't believe that Elinchrom works the opposite way.

[Frank Doorhof]

I tested it EXTENSIVLY with both my Elinchrom and a very cheap Jinbei and BOTH operate much faster on full power than on the lowest setting.

You don't have to believe me, try it for yourself.

There are indeed different ways of using capaciters but I know that Elinchrom told me that if you build a flash system the correct way it should be that on full power the flash duration is the shortest.

I have not the technical background to discuss that, but I know from my own experience that it works.
And that most people claim the opposite, but I also know that alot of people have BIG problems in freezing action

[godtfred]

Now that was an explanation...
Thanks a lot and I agree with you...
Not sure what hensel you thinking of because I looked into them a lot when I was on the quest for Short Duration flashes..  
In the Specs the Elinchroms are always way up there in the Short Duration...
Was going to buy some from B&H but they never have them in 240V? And went with another Brand..
Snook
Snook
[a href=\"index.php?act=findpost&pid=157714\"][{POST_SNAPBACK}][/a]

The Elinchromes miss out on the bayonet mount and the "plastic feeling" for me, but now I have this info on sync speed, I may get myself an RX 1200 power pack with a couple of heads, looks like a very good sync speed at a great price point!

-axel

[EricWHiss]

I tested it EXTENSIVLY with both my Elinchrom and a very cheap Jinbei and BOTH operate much faster on full power than on the lowest setting.

You don't have to believe me, try it for yourself.

There are indeed different ways of using capaciters but I know that Elinchrom told me that if you build a flash system the correct way it should be that on full power the flash duration is the shortest.

I have not the technical background to discuss that, but I know from my own experience that it works.
And that most people claim the opposite, but I also know that alot of people have BIG problems in freezing action
[a href=\"index.php?act=findpost&pid=157719\"][{POST_SNAPBACK}][/a]

If anyone close to San Francisco wants to test the Elinchrom strobes, I am happy to offer up my studio and mumford time machine with light cell for testing.  Frank and I went around this subject a while back on the Open Photography forums which is what prompted me to test my profoto D4 and portable canon and metz flash units.   These all got slower as power went up so I am really curious to know about the elinchrom.  I'm sure if Frank uses them its true, but I would be interested to measure them.  

I do see that some power packs now allow you to set the flash duration - so that is cool, but why wouldn't you always want the fastest?  Is there a case where you would want a slower duration flash?

[jpop]

I do see that some power packs now allow you to set the flash duration - so that is cool, but why wouldn't you always want the fastest?  Is there a case where you would want a slower duration flash?
[a href=\"index.php?act=findpost&pid=157722\"][{POST_SNAPBACK}][/a]

The blur during the exposure might be desirable and in some instances it might be conducive to have quick flash duration from one head while having long duration from another.  This could leave a trailing effect from a moving subject while the hero portion is tack sharp and motionless.

[EricWHiss]

The blur during the exposure might be desirable and in some instances it might be conducive to have quick flash duration from one head while having long duration from another.  This could leave a trailing effect from a moving subject while the hero portion is tack sharp and motionless.
[a href=\"index.php?act=findpost&pid=157727\"][{POST_SNAPBACK}][/a]

Yeah but could you not do this more easily with a hot light and a strobe with camera set to 2nd curtain?

[jpop]

Yeah but could you not do this more easily with a hot light and a strobe with camera set to 2nd curtain?
[a href=\"index.php?act=findpost&pid=157738\"][{POST_SNAPBACK}][/a]

I believe you could control this much easier with strobe and independent of shutter speed.  More creative control with variable flash duration settings at various power levels.  Certainly lots of way to get it done.

[mmurph]

Try the older Broncolor Pulso A4.

You can dial in the exact flash duration that you want, just like on the Grafit.  But being the previous generation predecessor to the Grafit they are much less expensive.  They sell for about $1,750 used.

They do have shorter durations as the power is reduced.  Many people use a bi-tube head, either on the same pack (to get slightly more power out at the same duration) or on two packs.

I have them here if you want me to check on power at a specific duration, also have the manual.  Great units!

Bron cites speeds in t0.1 most of the time, as mentioned. That is usually about 3x as long as teh t0.5 time that most manufacturers cite.

Best,
Michael

[jpop]

Bron cites speeds in t0.1 most of the time, as mentioned. That is usually about 3x as long as teh t0.5 time that most manufacturers cite.

[a href=\"index.php?act=findpost&pid=157781\"][{POST_SNAPBACK}][/a]

Actually that's backwards, t0.1 is the duration all the way down to when the flash exposure is 10% of peak output as opposed to t0.5 which is measuring duration at 50% of peak output.

[mmurph]

Hi John!

I may not have said that correctly. What I meant to say, quoting Broncolor, is that if you have the t0.5 time that most manufacturers give, you can estimate the t0.1 time by multiplying by 3.

For example, if you have a t0.5 time of 1/750, multiplying by 3 gives 3/750 or 1/250. That is the approximate "stopping power" of the flash without blur.  

That is because with the t0.5 time, as John mentions, only 50% of the flash discharge power has been completed.  That extra 50% causes some motion blur. With a t0.1 time, only 10% is remaining, which is negligible.

So when you have a 1/5,000 t0.1 time from Bron, that is much shorter duration than an equivalent t0.5 time you might see in someone elses spec.  

The best intuitive explanation I have heard is that t0.1 is more like a "shutter speed" time in terms of stopping power.

There is a nice discussion, and some examples, beginning on page 8 of this Broncolor PDF on the Grafit:

http://www.bron.ch/_data/bc_do_bs_grafitaplus_en.pdf

As others have mentioned, the Profoto Pro 7 and D4 packs also have very good specs.

Best,
Michael

[EricWHiss]

The coefficient in front of the T refers to the amplitude of the intensity discharged so is not a percent but Michael is correct in that the .1T is longer than the .5 T

For most packs, the discharge is normally very much like a bell curve so the point from .5T on the way up to .5T on the way down is not necessarily a percentage.  The more modern packs might even clip the tails of the curve or do something different in the delivery of the power to the flash tube, and I think the Brons control the curve with electronics so I don't know how it looks.    But in any case to find out how much light is actually put out during the different points on the curve, you would have to take the integral (find the area) between the points.  I'm pretty sure that if you did, (and I don't think many of us are interested so lets skip that part okay), you'd find that the amount of light between .1T and .5T up and .5 T and .1T on the way down is so much less than the amount between just the .5 that most companies sort of cheat and don't report the longer duration .1T times since it does not affect the image that much.  The tail of the curve is long but low and it doesn't put out much light.  

All that crappola being said  a 1/5000 duration at .1T specs for the Broncolor is very good indeed.  Next time I upgrade my strobes I know which one to buy!

[Dustbak]

The Elinchromes miss out on the bayonet mount and the "plastic feeling" for me, but now I have this info on sync speed, I may get myself an RX 1200 power pack with a couple of heads, looks like a very good sync speed at a great price point!

-axel
[a href=\"index.php?act=findpost&pid=157720\"][{POST_SNAPBACK}][/a]

I use the RX's for some years now. They are excellent quality for the price you pay. Fast, reliable, precise and very good pricing!

[Frank Doorhof]

This is straight from the technical department from Elinchrom.
A copy/paste from a mail a while ago when I was filming the Guide to modelphotography DVDs, I wanted the part on jump photography exactly right so I asked them because there is ALOT of talk about it online.

This is their answer.

Style RX for example:
At full power the flashduration is 1/2625 s
At  half power the flashduration is 1/1870 s
At minimum power the flashduration is 1/1380 s
 
Style FX:
At full power the flashduration is 1/900 s
At minimum power the flashduration is about 1/600 s

they called me about it to explain it more in depth and according to the person I spoke it works that way for MOST modern flashunits, they gave me an example of a balloon.
When it's full and you put a needle in it it explodes at once.
When it's not 100% full it will slowly die but not explode.

I tested it after that phone call with both my Jinbei (old leftovers ) and FX/RX/Dlites/Rangers and on ALL it was clearly seen that full power was faster than low power.
On low power I could hardly get the face sharp, on full power even the hairs were frozen on the RX and the feet slightly blurred.

I don't know what other brands do, but according to what I heard from several other people most use this technique.

Again my technical knowledge is not sufficiant to explain it in depth, but I do know what I see


Greetings,
Frank

[PatrikR]

I do see that some power packs now allow you to set the flash duration - so that is cool, but why wouldn't you always want the fastest?  Is there a case where you would want a slower duration flash?
[a href=\"index.php?act=findpost&pid=157722\"][{POST_SNAPBACK}][/a]

Broncolor Grafit allows you to set the flash duration but only at smaller power settings.

[Snook]

This is straight from the technical department from Elinchrom.
A copy/paste from a mail a while ago when I was filming the Guide to modelphotography DVDs, I wanted the part on jump photography exactly right so I asked them because there is ALOT of talk about it online.

This is their answer.

Style RX for example:
At full power the flashduration is 1/2625 s
At  half power the flashduration is 1/1870 s
At minimum power the flashduration is 1/1380 s
 
Style FX:
At full power the flashduration is 1/900 s
At minimum power the flashduration is about 1/600 s

they called me about it to explain it more in depth and according to the person I spoke it works that way for MOST modern flashunits, they gave me an example of a balloon.
When it's full and you put a needle in it it explodes at once.
When it's not 100% full it will slowly die but not explode.

I tested it after that phone call with both my Jinbei (old leftovers ) and FX/RX/Dlites/Rangers and on ALL it was clearly seen that full power was faster than low power.
On low power I could hardly get the face sharp, on full power even the hairs were frozen on the RX and the feet slightly blurred.

I don't know what other brands do, but according to what I heard from several other people most use this technique.

Again my technical knowledge is not sufficiant to explain it in depth, but I do know what I see
Greetings,
Frank
[a href=\"index.php?act=findpost&pid=157834\"][{POST_SNAPBACK}][/a]

Frank would you care to share what MOST OTHER flashes do it that way also you are talking about??
I cannot think of any? I agree with you that Elinchrom is that way and I always new they had the Shortest Flash Duration in their Medium Class Mono Blocks But,
MOST modern Flashes is exaggerated quite a bit.
Actually Elinchrom is the ONLY one I now know that does this.
Broncolor I cannot comment either. But like I said before.
MY MODERN Flashes:
Profoto
Hensel
Bowens
Do JUST the opposite. Shorter Duration at Lower Settings.
Good Luck...
Snook

[jpop]

Broncolor Grafit allows you to set the flash duration but only at smaller power settings.
[a href=\"index.php?act=findpost&pid=157864\"][{POST_SNAPBACK}][/a]

Actually the Broncolor Grafit lets you adjust flash duration throughout the range with the exception of at full power.  For the fastest flash duration settings you certainly need to be at the lowest power settings, as it's skimming the top of fully charged capacitors, the portion in which they discharge the fastest.  

I wish Broncolor would also advertise there t0.5 numbers.  Although I believe they are somewhat a misnomer with so much light coming from the trailing edge of flash duration, at least we would have some real comparative numbers.

[godtfred]

I wish Broncolor would also advertise there t0.5 numbers.  Although I believe they are somewhat a misnomer with so much light coming from the trailing edge of flash duration, at least we would have some real comparative numbers.
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Don't they?

If you follow this link:

[a href=\"http://www.bron.ch/_data/bc_do_ds_graftita2rfs_en.pdf]http://www.bron.ch/_data/bc_do_ds_graftita2rfs_en.pdf[/url]

the .pdf states both t0.1 and t0.5 numbers. If I recall correctly all the .pdf spec sheets from bron state this?

-axel

[jpop]

Don't they?

If you follow this link:

http://www.bron.ch/_data/bc_do_ds_graftita2rfs_en.pdf

the .pdf states both t0.1 and t0.5 numbers. If I recall correctly all the .pdf spec sheets from bron state this?

-axel
[a href=\"index.php?act=findpost&pid=157884\"][{POST_SNAPBACK}][/a]

Thanks!  Good to know and obviously my data sheets are older.  

Also interesting is looking through my older literature and finding the introduction of the Grafit flyer, the state of the art power pack is now 11 years old.  Doesn't seem like it was introduced that long ago .

[jpop]

Here are the t0.1 numbers from a Broncolor Grafit A4 pack using a twin head (flash duration would be the same for two heads).  The t0.1 rating as opposed to the t0.5 is two to three times as long as t0.5 measurements and a more accurate measurement of flash duration

3200ws     1/265th

1600ws     1/875th

  800ws     1/2000th

  400ws     1/3250th

  200ws     1/4900th

  100ws     1/7000th