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Radio triggers: An overview

Wireless triggers to fire flashes or the camera's shutter
by Gisle Hannemyr

This article is an introduction for photographers looking for radio triggers for flash and digital cameras. A lot of different triggers exists, and this article tries to gives an overview for the entire field, with links to other articles that discusses specific radio trigger systems.

If you also are interested in optical triggers, please see this article.

While optical triggers may be fine for wireless control of off-camera flash indoors, nothing beats radio for range and reliability outdoors. Also, if you want to have off-camera flash inside cars or behind furniture, radio is your best option.

Radio Frequencies

Several radio bands are made available for more or less unregulated use in different geographical areas this includes the bands used for RKE (Remote Keyless entry, i.e. garage openers) in North America, and the ISM (Industrial/Scientific/Medical) bands.

Equipment designed to operate in these bands is designed to be tolerant for interference by other equipment operating at the same frequency.

The common ISM and RKE bands available for industrial and commercial applications are:

  • 220 MHz (ISM, China).
  • 315-317 Mhz (RKE, North and South America, Japan).
  • 340-354 Mhz (ISM, North and South America).
  • 433-435 Mhz (ISM, Europe, Australia, Africa, China, India and some other countries).
  • 869 MHz (ISM, Europe).
  • 900-930 MHz (ISM, North America, and some other countries).
  • 2.4 GHz (ISM, worldwide).

Note that because of the different frequency allocations, use of the 315-317, 340-354 Mhz and 900-930 MHz devices is illegal in Europe, and the use of the 433-435 Mhz and 869 MHz devices is illegal in the USA.

Types of triggers

To make it simpler to find a particular trigger, we've separated the triggers into five types, as follows:

  1. Basic manual triggers
  2. Grouping triggers
  3. TTL pass-through triggers
  4. Premium manual triggers
  5. Third party dedicated TTL radio triggers
  6. Canon dedicated TTL radio triggers

At the end of each section describing the type, there is a list (with links) to those units that has been evaluated by DPanswers, along with an indication of what price you typically will have to pay for a kit consisting of one transmitter (TX) and one receiver (RX), or a pair of tranceivers. Note that one particular model may be listed more than once, if it has features matching the criteria of more than one type.

We plan to add more as we can find the time for testing. Watch this page for updates.

1. Basic manual triggers

If all you want to do is to trigger a manual flash or a camera's shutter release wirelessly by means of a radio signal, and you do not care about additional features such as grouping or TTL power control, then you're looking for a basic manual radio trigger.

This is the cheapest type of radio trigger available (for even cheaper, take a look at optical triggers.

The basic manual radio triggers are all produced in China and are sometimes referred to as Poverty Wizards or FleaBayTriggers.

2. Grouping triggers

A step up from basic manual triggers, both in price and in functionality, are triggers that let you operate groups or zones of flash units from camera position.

A grouping trigger let you distribute your remote flashes into groups or zones (usually 3 or 4). You can assign each receiver to belong to a specific group, and choose from the transmitter which of combinations of these groups you’d like to trigger. Grouping can save photographers a lot of time in complex lighting setups without having to go back and forth between flash and camera switching units on and off.

3. TTL pass-through triggers

A TTL pass-through trigger does not offer TTL wireless control. But the TX unit has a dedicated hot-shoe on top that pass-through the any TTL communication from the camera to a TTL commander mounted on top of the TX. The pass-through feature let you fire both TTL-controlled flash units (controlled by a commander mounted in the hot-shoe of the TX that is sitting in the camera's hot-shoe) and manual units (triggered by radio and connected to a radio RX) at the same time. However, the TTL computation does not take the light from the manually controlled units into account, so mixing modes like this is only practical when TTL is used for key and the manual units are used to light up the background.

4. Premium manual radio triggers

This segment consists of radio triggers that are built to take a lot of abuse, are very reliable, and packs a lot of power for an extended range. What they do not support is TTL exposure control, since that tend to have a negative impact on both reliability and range.

5. Third party dedicated TTL radio triggers

For some time, third party vendors has provided Canon and Nikon users with dedicated flash control systems that use radio instead of light to signal remote flash units.

While Canon has developed its own TTL radio protocol (described in the next section), no third party vendor supports this (yet). Instead, the third party dedicated TTL radio triggers currently on the market can be divided into into three different types. These are described below.

Systems simulating a wired connection

The most popular approach, used by four different manufacturers (PocketWizard, Phottix, Pixel and YongNuo) is to design radio units that makes the remote flash “believe” it is still connected to the camera. I.e. the remote flash is not set up to use the wireless TTL protocol that is part of any modern flash system these days, but is controlled by a radio relay circuit that relays the control signal from the camera's hot-shoe to the remote unit, just as you would do when using a TTL off-camera shoe cord to get the flash away from the camera.

All the systems in these groups let you use original flash units that support i-TTL (Nikon) or E-TTL II (Canon) as remote units, including units such as Nikon Speedlight SB-400 and Canon Speedlite 270EX that does not support the manufacturer's own wireless protocol. This is because the radio control systems simulate a wired connection, rather than relying on the manufacturer's own wireless protocol.

The most advanced of these radio control units let you operate multiple groups with power ratios, just as the manufacturer's light-based wireless systems do. The simpler units only let you control a single group with TTL exposure control.

Click for more detailed description:

Hybrid system using radio to relay IR

For a long time RadioPopper (established in 2007) was the only manufacturer that makes this type of hybrid system. However in 2012, Aokatec launched a competing product.

Unlike the radio systems that simulates a wired connection, hybrid relay systems uses IR-light to control remote units. However, to get around the range and reliability limitations of light, the system somehow intercepts the signal emitted by the master unit, converts it into radio signals, relay it, and converts it back from radio into light at the receiver end. This reconstructed IR-light signal is then fed to the remote flash's IR-port using fibre optics.

Because the system only relays the manufacturer's own light-based wireless protocol, it is compatible with it. This means that the photographer can freely mix remote units controlled directly by light, and by light relayed by radio.

Click for more detailed description:

Proprietary systems

The third and last type of system is prorietary. Unlike the two other type of dedicated TTL radio triggers, this type of system does not let you use the camera manufacturer's own flash units as remotes. Instead, you must use proprietary flash units with integrated radio receivers that is part of the radio control system.

Two manufacturers, Quantum and YongNuo offer this type of dedicated TTL flash control system.

Click for more detailed description:

5. Canon dedicated TTL radio triggers

In addition to its light-based flash control system, Canon also offer a full-featured radio based system for controlling remote flashes. The system operates in the 2.4 GHz band, and offers full E-TTL II support, better integreation, more features, and more groups than any of the third party radio control systems.

The main component of this system is the Speedlite 600EX-RT flash, which can be used both as a master on top of the camera, and as a remote (slave) Speedlite. There is also the Speedlite Transmitter ST-E3-RT. This can only be used as master on top of the camera. No Canon DSLR have (yet) a built-in radio master unit.

Both the 600EX-RT and the ST-E3-RT can be used to control up to 15 compatible Speedlites in up to five groups by radio.

For more information about Canon's flash system, see our introduction to the Canon flash system.

7. Final remarks

If you know about other radio triggers that deserves mentioning on this page, please use the comment field below to add your experiences.

Radio trigger suppliers:
Alien Bees
Bowens Pulsar
Elinchrom EL-Skyport
Gadget Infinity
Hensel Studiotechnik
Pixel Enterprise Ltd.
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22 responses:


I'm looking to buy a radiotrigger for my Nikon D300s – used with Nikon SB900 flashes.

I'm interested in one where you can adjust the output on individual flashes directly on the transmitter (and not thru camera menus).

I usually use my flashes in manual mode, so TTL-ability is not necessary.

I looked at “Pixel TTL Wireless Flash Trigger Set Knight TR-331”. Does this set give me the control that I want?

Hope somebody out there can help. Thanks!

Only with Speedlights SB-600 and SB-800

The Pixel Knight TR-331 for Nikon let you adjust the output on individual flashes directly on the transmitter, but not with the Speedligh SB-900, SB-910 and SB-700. This feature, however, works with the discontinued Nikon Speedlight SB-600 and SB-800. This feature depends on the legacy quench protocol, which is absent from Nikon's latest Speedlights.

For more information, see our Pixel Knight review.

YongNuo RF-603 for Canon Powershot G9

I'm looking for an inexpensive radio trigger for a canon G9 and a Vivitar 285HV. I like the YongNuo rf-603 but the manufacturer says it is incompatible with the G9. Is this only because the G9 does not have an external trigger or will this remote just not trigger with this camera? If it won't work does anyone have another suggestion.



You say the manufacturer says that the YongNuo RF-603 is “incompatible with the G9”. Where is this said? I have not found anything about compatibility (either way) on the YongNuo website. Nor have I ever tested the combination of Canon Powershot G9 and YongNuo RF-603.

However, the YongNuo RF-603 has a tranceiver construction that you mount in the camera's hot-shoe. It must be able to recognise the camera to operate correctly. If the Powershot G9 is not recognised by the tranceiver, it will not work. (However, since I do not have a G9 here for testing, I can't verify that this is the case – I would love to hear from anybody that has tested this particular combination.)

As an alternative, I suggest you consider the older YongNuo RF-602. It has a conventional design with a separate transmitter and receiver unit. I have found the transmitter to work in the hot-shoe of many different cameras, (including some non-Canon ones), so I am sure it will work with the Canon Powershot G9 as well.

G9 and RF-603

Thanks Gisle H.
When I did not find my camera on the compatibility list so I emailed the manufacturer through their store on Ebay. They say it is "not compatible" with no further explanation. What you say makes sense. I will continue to try getting a more extensive answer from the manufacturer and will ask about the RF-602 but I am not expecting any useful information due to the brevity of their previous communications. I too hope that someone here has tried one of these with the G9. I have a vague memory of seeing a list of compatible cameras which listed the G10 and G11 but not the G9. as being compatible but I can not find it again. The G9 does not have any type of external trigger for the shutter release so the RF-603 remote trigger function is useless. Since I do not need it I thought the G9 might be otherwise compatible.

I am hoping to see more information here.

Thanks again

New to strobist

I am new to strobist (well, heck! Photography in general...) and am researching heavily before making new purchases. I would like to use a wireless trigger only on my nikon camera hot shoe for nissin di866 and di622 flashes. Is this possible with any of the triggers mentioned to have it be iTTL? Or will I need to have the di866 be the master and on my camera body? Sorry if this seems stupid...thanks in advance!


there is a list of radio triggers that will give you iTTL above, in the section with the headline dedicated TTL radio triggers. You need to buy the Nikon version to have it work with iTTL.

If you want to use light instead of radio for wireless communication, then the Nissin Di866 in the camera hot-shoe can be used to wirelessly control the Nissin Di622 Mark II. Note that you need the Mark II version of the Nissin Di622 for this to work – the original version of the Nissin Di622 Speedlight did not support the iTTL wireless mode.

Also note that many Nikon DSLRs (but not D40, D40x, D50, S60, D3000, D3100, D5000, D5100) can wirelessly control the Nissin Di822 and the Nissin Di622 Mark II with light using the camera's pop-up flash as wireless master. Nikon calls this “commander mode”. If your Nikon camera supports it, there should be a section about “commander mode” in the camera's manual. Using the camera's pop-up flash is an alternative to using the Di866 on camera as master.

di866 mkII strobe

Can the strobe mode be used with cameras which don't have that settings (like D3100, d5100..thay allso don't have commander mode neither high speed sync)?



The Nissin Di866 Mk II is not a radio trigger. It signals using light.

If you want to know about the Nissin Di866, please see our article about the Di866. Ask below that article if something is still unclear.

Yongnuo RF603 and Metz 45CT5

I'm thinking of using a radio trigger to fire my Metz 45CT5. According to a few sites, the Metz unit has a trigger voltage of 14.8v, which is slightly higher than the Yongnuo max of 12v. Now the rest of my flash units are way higher, so I'm planning to trigger them with optical slaves (cost is far lower than kitting out with a Cactus setup) Question is, what flex is there in the trigger voltage for the RF603 - is 14.8v going to cause irrepairable damage ?

Receivers fired by Nikon Commander mode

I'm looking for wireless receivers that could be used with studio (or hot shoe type) strobes that I can fire wireless via Nikon Commander mode on a D700. Do they exist?


Ken wrote:

I'm looking for wireless receivers that could be used with studio (or hot shoe type) strobes that I can fire wireless via Nikon Commander mode on a D700. Do they exist?

No, they don't.

Fotga RF-2400

I purchased a couple of those Fotga RF-2400 knock-offs of the RF-602. The only issue I had with them was the need to cover 4 of the contacts on the receiver shoe with tape (leaving just the central large contact and a single small one uncovered) to achieve proper funtioning with the E-TTL YN-465 flash. Although it's sold for a Canon 550D, there are 6 contacts of different sizes on the hotshoe. This looks a little different than the contact pattern on the YN-465 flash shoe which only has 5 equally-sized contacts to exactly match those on the Canon camera shoe. Interestingly, I was able to achieve some success without the tape by cleaning and drying the contacts of the receiver and flash immediately before use. I would like to know if anyone beside me has purchased one of these Fotga knockoffs and has tried flashes with trigger voltages approaching the published 12-volt limit of the Yongnuo RF-602. I have a Starblitz DTS 3000 which has a 10.7 volt trigger voltage but don't want to risk frying one of my receivers.


What about The CyberSync™ System from Paul C. Buff? Have you reviewed them? And how do they rank to the rest you've reviewed?

Safe voltage for Pixel King?

Hello :)

Can I trigger with the Pixel King flashes with higher voltage on the shoe? :-)

Or which triggers allows to trigger high voltage flashes?



the Pixel King is reported to be able to handle flashes with a trigger voltage up to 36 volt.

d5100 and di622 mark II

i have a nikon d5100 and i am planning to get a nisiin di622 mark II. my question is, can i use the di622 mark II off cam with my d5100 or there is still a need for me to get wireless trigger?
thank you.

Nikon D5100 and off-camera flash

The Nissin Di622 II has a built in optical slave function that you can use to get the flash off-camera. You use the pop-up flash on your D5100 as lead flash. This will work fine indoors, but outside in bright sunlight you will probably want to use radio.

Note that this will be manual operation only. If you want off-camera flash with i-TTL control, you need to get a commander module such as the Nikon SU-800 to put in the hot-shoe of the D5100.

Godox Cells flash trigger

I can't find any review of this trigger. The page from Godox doesn't say if it is TTL capable.
Please comment on this anyone?

Godox Cells II flash trigger

DPanswers has not had access to the Godox Cells II flash trigger yet, so we cannot offer hands on information. I agree that the data sheet has very little information. However, since there is no mention of TTL in the specifications, and the hot-shoe shown in the photographs is incompatible with TTL, so I am pretty sure that this is just a grouping trigger that does not support TTL.

The specifications also claims 1/8000 second sync speed. I am pretty sure this mode is not compatible with HSS (Canon) or FP (Nikon), but instead is so-called hypersync. This is a technique that triggers the flash just before the shutter opens to exploit that the flash at full power lasts longer than 1/8000 second.

Search eBay for Godox Cells II.

PocketWizard MiniTT1 and FlexTT5

Good morning!
Have you analyzed the MiniTT1 and FlexTT5? Please see the manual on this wiki for more information: MiniTT1 and FlexTT5 Manual. Quote:

“The Canon MiniTT1 FlexTT5 radios work within the Canon E-TTL II system.
The Nikon MiniTT1 FlexTT5 radios work within the Nikon i-TTL/CLS system.
All references to TTL are exclusively for intelligent electronic systems or specific TTL for Canon (E-TTL II) and Nikon (i-TTL/CLS), and not film TTL.
The terms Speedlite or Speedlight are used interchangeably throughout this wiki.
This wiki contains the latest information about operating your radios.”

Could analyze this to see if it has the ability to control the power variation of flash shooting in TTL mode?

Thanks for your help!

Yongnuo RF 603 NII

Hello.I purchased the Yongnuo RF 603 NII as I am beginning to try doing studio photography.I was given as a gift 2 pairs of strobes Mircopro.At present, I already have 2 Nikon speedlights 700 & 910.Is it possible to use the transceivers with mix speedlights and strobes?My cam is a Nikon D7000.What camera and flash settings do I need to do to burst all of them at the same time.Thanks and hope to hear from you soon.

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