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phaseone df 1/1600 flash sync

kipling

New member
I have a question about the flash sync on the phaseone df with ls lenses.

I was at large equipment rental today ordering lights for an upcoming shoot next week where I need hi speed flash sync.

It was suggested to me to use the Broncolor Grafit 4's because with them you can dial in the flash output and the generator will show the specific flash duration at that power setting.
In this manner you can actiually see that you're output is within the sync duration of the shutter speed and so find the peak power output that the Grafit 4 can give you at your highest sync speed.

Well, I've been mislead too many times to leave it to chance, so I had them set up the lights that I will be using to test the setup.

I tried three different ls lenses on two different 65+ backs and two bodies with air sync transmitters and hard wired.
In every scenerio I would get the full flash output at shutter speeds of 1/125th of a second. Above that shutter speed the power would decrease exponentially.
At 1/1600th I was getteing about 4 stops less light.

This doesn't make sense to me because by using the output level of the Bron power pack that gives me a flash duration of 1/1600th I should not be cutting the power of the fash by moving from 1/125 to 1/250th...

Nobody at the rent studio could explain the problem.

I think I have an idea what it could be, but maybe someone here could confirm or correct my assumtion.

I suspect that the firmware of the back or the body isn't up to date.

I think the back was 1.2.1, I'm not sure though, because I didn't have a manual to find out how to check the firmware.

Anyway, if anyone knows what the problem might be I'd appreciate the help.
 

dougpeterson

Workshop Member
I tried three different ls lenses on two different 65+ backs and two bodies with air sync transmitters and hard wired.
In every scenerio I would get the full flash output at shutter speeds of 1/125th of a second. Above that shutter speed the power would decrease exponentially.

- Must be with LS lenses.
- Must be a 40+ or 65+ with "extended flash sync" (almost all are, but a very small number of them are out there from the first month or so before that feature was finalized - talk to your dealer if you are such a user).
- Air remote must be "fast" mode which decreases range and battery life but increases sync speed.
- must be an air remote and receiver (fast mode) or hard wired as most wireless transmitters cannot sync past 1/400th or so
- must ensure the body is set to use the LS shutter not the FP shutter

Some of these you touched on and I only included to make sure others looking at this list saw a complete list.

5.1.8 firmware is the latest on the back. Go to [menu > configuration > about] OR look at the metadata in c1 of a raw file captured with it.

If the flash duration of the pack is sufficient there should be no (meaningful) loss of light.

Doug Peterson (e-mail Me)
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Kai Birkigt

New member
I had good results with my P65+ before the firmware update but the local dealer told me better to do the upgrade. So I did it and still have good results (using Profoto flash equipment).

You can find out about the fw version by pressing "Menu", "Konfiguration" and way down "Info" (german).

All the info there is a bit confusing, because one can see six version infos. At the moment I don't know which one is important. I am sure somebody knows it.

Regards
Kai

P. S.:

I did it with Pocketwizards.
 
Last edited:

kipling

New member
Must be with LS lenses.
Tried 2 different LS 80mm and one LS 110mm

Must be a 40+ or 65+ with "extended flash sync" (almost all are, but a very small number of them are out there from the first month or so before that feature was finalized - talk to your dealer if you are such a user).
We tried two different bodies. it would surprise me if both were of the first few cameras without "extended flash sync". But it is possible.

Air remote must be "fast" mode which decreases range and battery life but increases sync speed.
Yes, Air remote was in the fast mode.

must be an air remote and receiver (fast mode) or hard wired as most wireless transmitters cannot sync past 1/400th or so.

Yes, Air remotes, both receiver and transmitter. And hard wired with two different sync cables.

must ensure the body is set to use the LS shutter not the FP shutter
Yes, LS lenses and LS showing in the control screen.

5.1.8 firmware is the latest on the back. Go to [menu > configuration > about] OR look at the metadata in c1 of a raw file captured with it.
This is the only thing I'm not certain of.

If the flash duration of the pack is sufficient there should be no (meaningful) loss of light.
The power pack seemed to be fine. But just to make sure I tried a Profoto 8a generator set at different output levels. Same problem.

Thanks for the info.
 

Jack

Sr. Administrator
Staff member
FWIW, you also need -- read MUST HAVE -- a flash duration of something SHORTER than 1/3200th of a sec from the flash to get a "full power" 1/1600th sync. This has to do with the way leaf shutters work, your flash duration has to be less than half the shutter speed you are trying to sync with. Most AC packs will not achieve a 1/3200th sec durtion unless they are the very latest versions of fast-cycle flash heads and packs. For example, my Elinchrom 3000 even with A heads will get to 1/1600th sec duration at low power, and so I can sync my LS lens at 1/800th with it. My Quadra will make 1/6000th with the "A" (fast Action) head at the lower powers, so I can sync with my LS lens at 1/1600th at the lowest 2 power settings. Moreover, if you have a flash with a 1/1600th duration, and sync with an LS lens at 1/1600th, you will loose about 1 stop of actual light for the exposure, and it only gets worse as flash duration increases.

Cheers,
 

dougpeterson

Workshop Member
Must be a 40+ or 65+ with "extended flash sync" (almost all are, but a very small number of them are out there from the first month or so before that feature was finalized - talk to your dealer if you are such a user).
We tried two different bodies. it would surprise me if both were of the first few cameras without "extended flash sync". But it is possible.
.
It's the BACK not the BODY which must have "extended flash sync". I agree it's unlikely that they were both such early versions that were never upgraded, but not impossible.
 

dougpeterson

Workshop Member
All the info there is a bit confusing, because one can see six version infos. At the moment I don't know which one is important. I am sure somebody knows it.
Main. This number is usually something like 4.8.8, 5.1.2, or 5.1.8.

It should be 5.1.8 currently.
 

kipling

New member
FWIW, you also need -- read MUST HAVE -- a flash duration of something SHORTER than 1/3200th of a sec from the flash to get a "full power" 1/1600th sync. This has to do with the way leaf shutters work, your flash duration has to be less than half the shutter speed you are trying to sync with. Most AC packs will not achieve a 1/3200th sec durtion unless they are the very latest versions of fast-cycle flash heads and packs. For example, my Elinchrom 3000 even with A heads will get to 1/1600th sec duration at low power, and so I can sync my LS lens at 1/800th with it. My Quadra will make 1/6000th with the "A" (fast Action) head at the lower powers, so I can sync with my LS lens at 1/1600th at the lowest 2 power settings. Moreover, if you have a flash with a 1/1600th duration, and sync with an LS lens at 1/1600th, you will loose about 1 stop of actual light for the exposure, and it only gets worse as flash duration increases.

Cheers,
thanks for the info. didn't realize that.
unfortunately that doesn't explain why I was seeing a loss of light/exposure at anything above 1/125th. The power pack was set to an output level that produced a flash duration of 1/1600, so according to your info I should get full output at 1/800th, but I was getting about three stops less at that shutter speed.

good info regardless...thanks.
 

kipling

New member
just in case I can't get this resolved in time, does anyone know which flash power unit brand/version will give me the highest flash output at the shortest duration?
I'd like to reach f11 at 1/125th with the shortest flash duation to help me freeze as musch motion as possible.

thanks!
 

UlfKrentz

New member
Hi,

you were well advised with the bron packs. We are working with Grafit and Scoro packs for a long time now, they use a technology of switching off the output after a defined time that can be user influenced. Pro8 or Pro7 might be a bit faster at highest power levels as they use a higher voltage. I still have to make a personal test, don´t have enough time...but never regretted buying into the broncolor system.
What I would highly recommend is the use of a twin head as this will half the flash duration. This will work with either broncolor or profoto.

Cheers, Ulf
 

kipling

New member
Hi,

you were well advised with the bron packs. We are working with Grafit and Scoro packs for a long time now, they use a technology of switching off the output after a defined time that can be user influenced. Pro8 or Pro7 might be a bit faster at highest power levels as they use a higher voltage. I still have to make a personal test, don´t have enough time...but never regretted buying into the broncolor system.
What I would highly recommend is the use of a twin head as this will half the flash duration. This will work with either broncolor or profoto.

Cheers, Ulf
thanks ulf, good point with the twin head.
 
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