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Sekonic L-758 with RT-32CTL, PocketWizards & Nikon Speedlights


(This post is exclusively about the Nikon Based Pocktwizard Flex TT5 and MiniTT1 units)

In the past Sekonic light meters with transmitter triggers were not capable of triggering PocketWizard mounted remote Nikon Speedlights to output the light values specified by PockeWizard mounted on camera commander units.

If one wanted to trigger the speedlights with a Sekonic light meter, light output had to be specified manually from the Speedlights themselves. The way around was to specify the light output with the on-camera commander unit and to take a “dummy shot” to fire the speedlights.

Sekonic’s latest Radio Trigger RT-32CTL and the firmware updates for the Sekonic lightmeters and PocketWizards Flex and Mini units address this issue and make the entire process much more convenient for photographers.

For example; If you place a Nikon Speedlight on a PocketWizard FlexTT5, and then mount a commander unit (AC3/SU800/SB800-910) on to an OFF CAMERA transmitter FlexTT5 or MiniTT1 and choose the output from the AC3, now you can fire the setup from the your Sekonic and get the light output specified by the AC3.

Photographers can now place three lights (groups) wherever they want, walk up to the subject and fire the lights from Sekonic and make the changes from TT5/TT1 mounted OFF CAMERA commander unit and measure the light output.
How is that for convenience? No more running up and down, lowering light stands or opening up soft boxes.

Yes there are one or two bugs – but at the time of writing this post the firmware for PockeWizard Flex TT5 and Mini TT1 units are beta versions (3.110)

I have updated my Sekonic L758DR, all my Flex TT5 units and tested them with my seven Nikon speedlights.

Here is how to update and configure the Sekonic Lightmeter, Flex TT5 and Mini TT1 to work with the new Transmitter unit RT-32CTL

This is how I configured the system to work for what I do – channels and configuration settings are interchangeable.

For this example I have used

  • Sekonic L-758 Light meter fitted with NEW RT-32CTL Transmitter
  • PocketWizard FlexTT5 unit with the beta firmware (3.110)as the remote receiver
  • PocketWizard MiniTT1 unit with the beta firmware (3.110) as the on camera transmitter (A Flex unit can be used for this)
  • PocketWizard AC-3 Zone Controller as a commander unit to change the light output level.
  • Nikon SU-800 Commander unit as another commander unit change the light output level.

My configuration settings were as follows

  •   C1 configured to communicate via ControlTL channels. (For CLS and to use the new system)
  •  C2 configured to communicate and trigger via standard channels

(Configuring C1/C2 to communicate via Standard Channels gives the user the ability to use extra Speedlights in manual mode if required.)

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Start with the Sekonic Light Meter

  • (We are going to use ControlTL Transmit Channel 1 to trigger our Speedlights in Configuration C1, and Standard Channel 32 for Configuration C2)
  • Insert the the New RT-32CTL Transmitter unit to your Sekonic L-758
  • Download the latest firmware for your light meter and update the meter via Sekonic Data Transfer Software


Once the firmware is updated and the Wireless Flash Radio Triggering Mode is selected (Pages 28-30 of the L-758 Manual)  the display starts to show light meter’s new acquired ability to trigger ControlTL channels.

Note the CH1 before the A,B,C  (ControlTL 1 is selected/left alone at default)


Radio Trigger Module is designed to emit both the ControlTL transmit channel and Standard transmit channel signals at the same time.

L-758’s display automatically toggles to show the standard channels as well.  Note the selected standard channel  (32) before the A,B,C,D


Download the latest firmware and update your PocketWizard MiniTT1 and FlexTT5 units

Configure the PocketWizard Transmitter Unit

I have used a PockeWizard MiniTT1 as my transmitter unit. Mini TT1, despite it’s lack of “receiving” ability was able to act as the transmitter module – well done PW!

C1 was configured  for Control TL, Note the selected ControlTL transmit Channel  (1).

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Configuration C2 of the transmitter unit MiniTT1, as stated above, was configured for standard Channel 32. Note the selected Standard Channel (32)

Finally, Configure the remote receiving PocketWizard FlexTT5 unit

Note: Since this is the receiving unit, concentrate only on the lower “Receive” box, “Transmit” box area is of no importance unless you want to use this unit as a transmitter.

Configure C1 to Receive ControlTL signal

Make Sure to tick “Use ControlTL for Receive Channel” check box


Configure C2, to receive Standard Channel 32

Note: Configuration C2 is selected and “Use Control TL for Receive Channel” is UNCHECKED


Now you are ready to rock & roll.

The system works only in Manual mode, meaning you need to select “M” mode on your AC3 or SU800/SB800-910

I have checked the system with my PocketWizard AC3 Zone Controller and Nikon SU800 on a PocketWizard MiniTT1 on and off the camera. Yes it did work off the camera – which was the whole point!

At this stage, based on my testing the firing is about 95% reliable. Due to some strange reason the system was quite adamant at the start, and refused to fire. However, after the test button on the MiniTT1 was pressed just once, everything started to work fine.

At least couple of times the system “forgot” to change the power output once it was re-set with the commander unit, but one extra test trigger from the light meter sorted everything.

Hopefully PocketWizard will crush the bugs when they release the official firmware!

Disclaimer: Everything stated on this blog post was based on my personal testing and what worked for me during a single test shoot- your mileage will vary . It is your responsibility to check your system before a shoot. I take absolutely no responsibility for the way you set up your system or the reliability of it.



25 Responses

  1. Thank you, Dinil! This the first clear and comprehensive explanation of how the upgraded meter and PW radios might be configured and made to work together. I can’t wait to get started.

  2. Nice write up. Last week I shot with my Sekonic L-358/RT-32CTL, Nikon MiniTT1/AC3, FlexTT5s, SB-800 and PowerMC2s with Einsteins. The new beta firmware substantially improves the ability to take the MiniTT1/AC3 off camera and take meter readings with the Sekonic triggering all the remotes. Everything worked 90% of the time, but at one point, I couldn’t get the Sekonic to trigger with the AC3 settings (off camera) even with multiple Test fires directly from the MiniTT1 to set power levels. The Sekonic would trigger the lights, but no matter what was dialed into the AC3 the meter reading stayed the same. This occurred with the MC2s as receivers.

    Overall a very convenient way to adjust and meter with the Sekonic and ControlTL system. Hope the production release solves some of the beta issues that I encountered.

    1. Craig,
      I did a shoot two days ago and same thing happened to my set of PocketWizards. After about 40 images Sekonic L-758 as well as the the Mini with AC3 refused to trigger the remote Flex mounted speedlights. The bug seems to be in the PW firmware, not the Sekonic module.

  3. That is exaclty what I was waiting for! Is this achievable with a Sekonic L-358 lightmeter ?
    Are the settings written in the exifs data when using a Nikon SB-900 ?

    1. Stephane,
      I don’t have a L-358 to test, but the above response by Craig Wu clearly suggests the system works with the L-358. The literature that came with Sekonic RT-32CTL and the Sekonic website also confirm this.
      I’m not too sure whether I clearly understood your last question or not; but if you are asking whether PocketWizards allow image metadata to record whether the flash was used or not the answer is yes; they do.
      Image metadata shows “Flash: fired”

      1. Thanks for your answer Dinil.
        For the last question, I thought about the data the Nikon CLS is writing i.e. the flashes groups settings. But after a check, they appear only in the NEF metadata under nikon software. Do you know if the pocketwizard allows this kind of data transfer when using a SB-900 in commander mode ?

        1. Stephane,
          Unfortunately I don’t use Nikon software, I tried to open a file in my old captureNX – 1 copy, but it refused to open D800 or D700 NEF files. Lightroom-4 only gave a single liner, aperture returned two.

  4. Hi and thanks for you post!

    could you help?

    Can you demonstrate via a video or written text how I can use my Nikon SU-800, with Flex TT5 and Mini TT1 to control multiple Nikon speed lights but still get the benefit of using the Nikon SU-800 as a commander (no line of sight)?

    Also for this set-up I use a Sekonic L-768 with RT-32CTL.

    Kind Regards,


    1. Hi Micheal
      Thanks for reading my blog, and apologies for taking such a long time to replay.
      As you can see I have moved this to a new domain away from Visible Range to keep the blog completely separate from the commercial activities of Visible Range. Hence the delay in replying and adding new content.

      Here’s the the answer to your question, if you haven’t already got it figured out:

      What you have on top of your MiniTT1 makes no difference to the way the system functions. You can use SB800/900/910, SU-800 or an AC3-Zone controller as the commander to specify the light output. When you put the SU-800 on top of a Mini all it does is informing the Mini what the required light output is, to be conveyed to remote FlexTT5 units. Communication with remote speedlights mounted on FexTT5 units happen entirely via PocketWizard’s radio signals, hence the line of sight, even though you are using SB/SU units is taken away from the equation, which is the main advantage of using PWs.
      Personally, I much prefer the AC-3 because it is so easy to control compared to Speedlights and SU-800. SU-800 requires many button presses to change the light output, whereas AC-3 only requires a single rotation of a dial. I haven’t used my SU-800 since the day I bought AC3, which is more than two years!!
      I have no affiliations with PocketWizard or Sekonic, but if you are using PW Flex/Mini radios AC-3 would be one of the best little gadgets you can add to your system to make your life much less complicated than using the SU-800.
      Hope this helps..

  5. Dear Dinil

    i have the L-758dr bought about a yr back. it has a module in it but nothing written on it. i have upgraded the dts software and pw tt5 to 3.15 and L-758-dr already current version at 20 for windows).

    i cant seem to find any change in the display.

    am i missing something obvious.

    so far i have been using it to trigger my elinchroms via skyport but cant seem to trigger nikon sb-900 with them.

    can u help? i would be grateful

    1. Hi Rohit
      Good to hear from you and thank you so much for visiting my blog. As I have mentioned to Micheal, apologies for the lengthy delay in replying – This blog is now at different domain away from Visible Range where it used to be and all that took a bit of time.

      If you have bought the meter one year back, the module in your meter would most probably be RT-32N, instead of RT-32CTL
      The fact that you could trigger your elinchroms tells us that it is clearly working. Check out whether you can get the meter to trigger the PocketWizard mounted Nikons in full manual mode via standard channels (C2 configuration in the post above). In this mode camera mounted TT1 or the controller doesn’t do anything and your meter will directly communicate with the Flex units to fire the mounted speedlights. Light output will have to be changed manually on the speedlight.

      As far as I know RT-32CTL is universally compatible with all PocketWizard radios irrespective of the receiving radio’s specified frequency zone. I bought my RT-32CTL from the US the moment it got available and it works flawlessly with my “EU specified” Australian Sekonic L-758 and PocketWizards.
      Hope this helps ….pl let us know the outcome of your exercise..

  6. Dinil,

    Thanks for a great post. I’m almost there getting it to work – I have a question.

    I bought a 758 DR end of 2013 which already has the 32CTRL unit built in (bonus!)

    I have downloaded the latest versions of the software for the TT1 and TT5 and found it only works when the AC3 is in Manual mode (as you state above) – however in the video Mark Wallace did for Sekonic, he does it all using iTTL?

    It’s been a while since you wrote the post and the software/ firmware has changed – have you since this blog post been able to get it to work in iTTL mode?

    Thanks in advance

    1. Thanks for commenting Johan,
      If you are asking whether the speedlights fire when switched to “A” mode on AC3, the answer is yes. Sekonic/32CTRL also fire the TT5 mounted speedlights even when the TT1/AC3 combo is switched off. What I have noticed so far is that the FlexTT5 units seem to retain the “last specified light output value” from the AC3 even when the AC3 is switched off and just outputs that value when it receives the firing command from Sekonic. My firmware versions are current but I’m not too sure whether this is a bug or not. I’ll have to test things bit more comprehensively to confirm this.

      Having said that, using the A/iTTL mode sort of beats the purpose of using a Sekonic/Light meter. A/iTTL mode does it’s own thing and automatically specifies the light output!

      I have never tried this combo in “A” mode, so I cannot comment whether the exposures are similar to what ‘pure’ iTTL without PWs would produce. I will keep your questions in mind when I shoot again with speedlights.

  7. Dinil,

    Great post !!! I bought my Sekonic RT-32N long ago to work with my L-358 Sekonic LM, but I never managed to get it working. All it took was to match the receiving channel on the TT5 to the same channel as the RT-32N module. You are a genious ! Thanks a lot.

  8. I do not have a Sekonic meter yet but gonna get the 758dru. Now with this meter will it trigger my flex tt5’s? If so I also have the ac3 zone control. Will the 758 dru trigger these tt5’s and what about the power control with the 758? To control each zone abc etc

    1. Hi Lindsey
      Glad to know people are still reading this old post!
      I guess you are in USA, right?
      Just make sure that your tt5 and your Sekonic are ‘US’ models. Triggering frequencies for US (as well as few other countries) are different from the rest of the world. If your TT5s are US, and the 758 is going to be US, there shouldn’t be a problem.
      You CANNOT control the power with 758, for that you need a Mini/TT5 mounted controller (AC3 or a Nikon commander unit). However, you can take the TT5+AC3 off camera and keep it in your hand and control the power while triggering and measuring with the meter.

      1. Thanks so much. Well still debating on which meter. All my stuff is Nikon and yes do have a ace. A tt1 and 3 tt5’s. Made that decision for me as to Which meter The 758dru or the 478 dru. Lol

        1. I have never tried the 478; Having the ability to set the light output from the meter is cool; AAA batteries are much more easier to find and cheaper than CR123A batteries.
          On the other hand dials and buttons would be much convenient on the set, especially if you are one of those people with sweaty hands. If you go for bigger lights, they come with skyports & air remotes etc..

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