Definitive Guide To Medium Format High-Speed Sync

 In Broncolor, Hardware Tests, Phase One, Profoto, Tech
Capture Integration | Medium Format High Speed Sync

Note: The information on this page has been expanded upon in greater detail in a new post on Flash Durations vs High Speed Sync.Maximum flash sync speed is an incredibly important, yet elusive piece of knowledge that can be difficult to keep track of. With the same back and body, different sync speeds can be achieved with different lenses. Alternately, with the same lens and body, different digital backs can sometimes achieve different sync speeds. In an effort to demystify what-kit can achieve what-sync speed, we’ve housed many practical combinations of flash synchronization speeds into an easy to read table below.Click here to jump straight to the table or read on for important info about the test.


When we talk about sync speeds we have to talk about shutters. The two types of shutter used most in medium format are focal plane shutters and leaf shutters.

Focal plane shutters are housed in the camera body and by-and-large can sync at a maximum of 1/125th of a second, but has a much faster maximum shutter speed. This is due to the fact that the focal plane shutter is divided into two curtains. Any shutter speed faster than 1/125th of a second requires the second curtain to begin covering the sensor before the first curtain has completely retreated, creating a black bar when the flash fires.

Leaf shutters are housed in lenses, and can generally sync at speeds faster than 1/125th. Leaf shutters are named so due to the petal type components of the shutter. When a leaf shutter lens is being employed, the shutter closes just before capture, opens evenly in a circular shape for the duration of the exposure, and closes in the same way at the end of the exposure. This process allows for the whole sensor to be covered by the flash at the same time. The flash sync speed for leaf shutter lenses is generally limited to the mechanical speed limitations of the shutter, and usually maxes out around 1/800th of a second.

The Test

Four different strobe configurations were tested on each combination of body, back, and lens. All items listed below were actually tested in our facility. Tech specs are often inaccurate, so we prefer to verify them with our own results. We will add combinations and systems upon availability to test. If you have a specific kit configuration you would like tested, please let us know so and we’ll try to accommodate requests.

The trigger configurations:

  • Pocketwizard Plus III triggering another Pocketwizard Plus III SET TO FAST mode on a Profoto Acute 2R 1200
  • Profoto Air remote triggering a Profoto D1 250
  • Broncolor RFS 1 triggering a scoro 1600E RFS
  • Hard sync to Profoto Acute 2R 1200

Pocketwizard Plus III

How to achieve 1/1600th of a second using Pocketwizard Plus III radio triggers (or the newer, USB MultiMAXes.)

The Pocketwizard Plus III radio triggers have the unique ability to sync at a surprising 1/1600th of a second with leaf shutters, even though they are only rated at 1/500th of a second. This is through a special mode called FAST mode.

This is accomplished by setting the Pocketwizard connected to your flash unit to HSR and setting the channel to any number above 17. Then, you will turn off any groupings (A, B, C, or D.) The display on the Pocketwizard Receiver will display an “F”. This indicates the flash is ready for high speed sync. Remember, FAST mode is different from HSR, so make sure you have the F displayed! On compatible MultiMAXes, this is done by hitting the Menu button, then A:Advanced Menu, then D:Fast mode. Or, something a little easier, just hit A, A, D, and you’re done! You can use both MultiMAXes and Plus IIIs as receivers for this functionality together.

Fast mode effectively shortens the processing time between the receiver hearing the incoming signal, and sending a “fire!” signal through the sync port. This is a change to the radio’s microprocessor routines, and strips data like Zones out (which is why you disable A, B, C, and D on the receiver.) This feature is not available on Plus IIs, PlusXs, FlexTT5s, PowerMC2s, PowerST4s, or older MultiMAXes.

The only requirements for the transmitter are to be in TX only, set to the same channel as the receiver, and at least one grouping (A, B, C, or D) to be activated.

This could be considered a hack for the Pocketwizard Plus IIIs, and as such, is not perfect. Shooting in one stop increments from 1/125th to 1/1600th will reveal imperfect steps of exposure: meaning going from 1/800th to 1/1600th may provide a ¼ stop loss in exposure when in theory there should be no such loss. This is usually due to a longer flash duration, and may be sidestepped by using a faster flash duration through a different flash head, different flash pack, or by adjusting your power level. Different flash manufacturers change their flash durations at different power levels. Elinchrom, for example, seems to have shorter flash durations at higher power levels, while other setups have longer flash durations at higher power. You may want to reference the manufacturer’s specs or support for more information.

While not perfect, the ability to sync at such high shutter speeds with such an affordable product is an asset, and a great piece of knowledge to keep in your back pocket as a photographer or digital tech.

Pocketwizard FlexTT5s and MiniTT1s are designed primarily for use with Canon or Nikon cameras and their proprietary flash units in TTL mode, and also to perpetuate the Canon and Nikon flash’s HSS mode of pulsing the light above Nikon/Canon camera’s X-sync speeds. Using leaf shutters with standard power systems such as Profoto and Broncolor, these radio triggers are mostly rendered obsolete, as these flash manufacturers do not currently make equipment compatible with the PocketWizard ControlTL radios. Using the FlexTT5 and MiniTT1 as a standard radio trigger on a Profoto D1, we found the sync speed to top out at 1/320th due to a lack of FAST mode.

What We Learned

We learned that the manufacturer specs aren’t always correct. After rigorous testing, we found the following pairings jumped out:

Kodak/Dalsa Sensors (on 645 DF+/DF)

  • Dalsa Sensors and Leaf Shutter Lenses will sync up to 1/1,600
  • Kodak Sensors and Leaf Shutter Lenses will sync up to 1/800
  • Both sensors and AF,Digital,Manual Lenses will sync up to 1/125

645 DF+/DF & Aptus II Backs

  • Leaf Aptus II Backs (1st Generation) will sync up to 1/800
  • Leaf Aptus II Backs (2nd Generation) will sync up to 1/1,600

1/1,600 sync on 645DF/DF+ with Schneider-Kreuznach LS lenses is enabled on all Aptus-II backs (M mount) with serial numbers starting from LI301000. Older models are 1/800.


  • 80mm Leaf Shutter Lens (when used with DF/DF+ and Broncolor RFS transmitter) will sync up to 1/500 (RFS2 will sync to 1/1600)
  • 240mm Leaf Shutter Lens will sync up to 1/1000 (all transmitters)
  • Leica S Sync: 1/125 s (body FPS) / 1/1000 s (lens CS), sync at all slower speeds, choice of first or second curtain sync; FPS flash sync at faster shutter speeds (1/180 s-1/4000 s) possible with suitably equipped flash units (HSS mode)

Leica SFocal PlaneLeica S1/125

Camera BodyLensDigital BackTrigger
645 DF & DF+Leaf ShutterIQ/Credo/P65+/P40+1/1600
645 DF & DF+Leaf ShutterAll Kodak Digital Backs1/800
645 DF & DF+AF, Digital, ManualAll Digital Backs1/125
*Aptus II backs (1st Generation) will sync up to 1/800 | Aptus II backs (2nd Generation) will sync up to 1/1600
*80mm LS lens will sync up to 1/500 on Broncolor RFS
*240mm LS lens will sync up to 1/1000 on Broncolor RFS
645 AF/AFD I,II,IIIAF, Digital, ManualAll Digital Backs1/125
Hasselblad HLeaf ShutterAll Digital Backs1/800
Hasselblad VLeaf ShutterAll Digital Backs1/500
Leica SCentral ShutterLeica S1/1000
Leica SFocal PlaneLeica S1/125
Contax 645Focal PlaneAll Digital Backs1/125
Mamiya RZ67Leaf ShutterAll Digital Backs1/400
Fuji 680Leaf ShutterAll Digital Backs1/400
Tech CamerasCopal ShutterAll Digital Backs1/500
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