Maximum Flash Sync Speed with 645DF+110mmLS+Profoto Air

Discussions regarding Phase One 645 DF / DF+ and Mamiya 645 DF / DF+
Also lens discussion for Phase One and Schneider lenses.

Maximum Flash Sync Speed with 645DF+110mmLS+Profoto Air

Postby NNN634657213803093054 » Wed Jun 27, 2012 4:18 am

I have a question concerning flash sync speeds.

My understanding is that flash sync speeds up to 1/1600s are possible with the 645DF + Schneider 110mm LS + Profoto Air.

My testing has shown less. Tests show syncing up to a maximum shutter speed of ONLY 1/800s.

Test Setup:

Mamiya 645DF
Schneider 110mm LS lens
Leaf Aptus II 7
Profoto Air Transceiver in 645DF hotshoe
Profoto Air Transceiver plugged in sync port of Profoto Pro-B2 pack

As soon as the shutter speed is set 1/3 stop faster than 1/800s, a black frame results.

The million dollar question.....
Why can't flash be synced up to 1/1600s as advertised?

Is this functionality only limited to use with the vertical grip? That would seem odd to me.

Please help.

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Re: Maximum Flash Sync Speed with 645DF+110mmLS+Profoto Air

Postby Paul_Steunebrink » Wed Jun 27, 2012 8:37 am

It is the V-grip that enables the faster sync speeds. And of course with the LS lenses as another prerequisite. Look for info on the grip here: ... tures.aspx
In paticular the first line of the section about the grip.
The Phase One V-Grip Air is the first vertical grip with an integrated flash trigger that allows sync speeds up to 1/1600s.
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Re: Maximum Flash Sync Speed with 645DF+110mmLS+Profoto Air

Postby Ulf » Wed Jun 27, 2012 11:27 am


This depends on if your Aptus-II have extended DF support or not.
If it does not (Aptus / Aptus S does not) you can only shoot 1/800
All new Aptus-II have extended mode (Serial number higher then LI031000) but older does not.

If your back has it or not can be verified by Support by raising a case and include the serial number of the back.
You back can be upgraded to support extended DF mode for a fee. Contact your local Leaf dealer to arrange this.
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Re: Maximum Flash Sync Speed with 645DF+110mmLS+Profoto Air

Postby FredBGG » Sat Nov 24, 2012 4:25 am


In the mean time if you need to go faster than 1/800th or even faster than 1/1600th there are ways to do so with
some DSLR camera if you have one. I have achieved 1/8000th.
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