Six Ways to Go Wireless With Your Flash
A big step in my progression with DSLR photography was finally getting an external flash, the next step was getting that flash off my camera and doing so wirelessly. In this post, I’ll talk about the myriad of options for going wireless with an external flash. There’s pros and cons for each option of course. Some are free while others can cost as much as your camera.
An external flash is commonly known as a Speedlite (Canon) / Speedlight (Nikon) and it’s designed to be put right on top of your camera in the flash “hot shoe”. Nowadays, however, an external flash forms part of a complex and highly integrated system. It’s an intelligent light source full of software and electronics that deeply integrate with your camera.
So why was an external flash such a big step? As soon as I began to control light, I began to create the shots I wanted vs. just recording what was in front of me. It forced me to really understand exposure and make creative decisions about light (e.g. mixing intensity, direction, spread, and other qualities of light).
At first, I started with the flash firmly planted on my camera. Quickly I tired of flat on-axis light so I learned how to effectively bounce my flash off ceilings and walls. One great technique I learned was how avoid direct light hitting the subject (see example).
Still, I knew the next major step was to use the flash off my camera. It would allow me to produce directional light without bouncing the light off another surface and I would gain tremendous creative freedom. In fact, since I was no longer restricted to the single flash shoe on my camera, I started considering multiple flash units being fired simultaneously. I have two flashes now (a 580EX II and a 430EX II).
The questions became…
- “Who do I trigger a flash while it’s not on my camera?”
- “How can I avoid crazy long wires?” and,
- “How do I control multiple flash units at the same time?”
These’s unfortunately few straightforward answers but the good news is there are many options available – all of which I’ve detailed for you in this post.
Flash 101: TTL vs. Manual Flash
Before I get into the discussion about remotely triggering a flash, it’s important to note that there are two distinct ways to control a flash (wired or wireless). In essence, you can either have the camera work in concert with the flash to set the correct power level or you can set the power level manually.
The automatic mode is referred to as “TTL” (Canon calls it “E-TTL” and Nikon calls it “i-TTL”) and it’s short for “Through the Lens”. In this mode, your flash and camera communicate in real-time to regulate the power of the flash without you even noticing.
While in TTL mode, your flash fires an extra burst of light a split-second before the “real” flash. This pre-flash bounces off your subject and back into the camera via the lens (hence “through the lens”). Your camera instantly evaluates if you need more or less light and adjusts the flash power appropriately. It does that extra step so fast that you only perceive a single burst of light (it’s hugely impressive).
As you can imagine, manual flash doesn’t make use of any pre-flash or fancy camera evaluation. You simply tell the flash to fire at its full power, 1/2 power, 1/4, power, etc. and it uses that strength consistently from shot to shot.
Calculating the required flash power, however, can be tricky. You have to memorize your flash’s power rating (its “guide number”) and do some mental math as it relates to your flash’s position relative to the subject being lit.
Automatic TTL mode is a real time-saver when the distance from you subject and the flash is always changing. You don’t have to calculate and or re-test your flash power on every shot. If the flash-to-subject distance won’t vary between shots, you might actually prefer a manual flash setting as you’ll get a consistent exposure across a series of shots.
I’m highlighting these differences now as some options for triggering your off-camera flash will remove your ability to shoot in TTL mode.
OK, enough background and onto your options for getting your flash off the camera with as few wires as possible.
Option 1: Built-in Camera-to-Flash Wireless Trigger
If you have a Canon 7D, 60D or T3i, you’re in luck as you have a built-in remote flash trigger. If you have the Nikon D40 or better, you probably have one as well.
Nikon refers to its wireless flash capability as being part of their “Creative Lighting System”. Canon hasn’t got a fancy name for it but they’re pretty much the same (Wikipedia: Canon EOS Flash System).
Naturally, if you have this capability in your camera and own a compatible flash unit, you’ll want to start here as this is effectively free and it works reasonably well.
That said, I have a Canon 7D and have used the Canon system extensively and I encountered a variety of issues. It’s a huge step forward but there are some serious downsides which may push you to consider alternatives as I did.
For these built-in systems to function, your camera uses its pop-up flash as a transmitter. The camera is referred to as the “master” or “commander” which controls “slave” or “remote” flashes.
With this option, you set all the flash options directly in your camera’s flash menu and you can get to use every single TTL capability offered without a single wire. You can also set manual flash power levels from the camera as well.
Both Canon and Nikon allow you to control three flash groups labeled A, B and C. Within these groups, you can trigger a near-unlimited number of flashes. The benefit of groups is the ability to have varying levels of power. You can even set them up with ratios (e.g. 2:1 for groups A:B so your key light is twice a strong as your fill light).
The biggest issue with this option is that the signal from camera to the flash is optical and not radio-based. Even your cordless phone and garage opener use more reliable radio-waves. Instead, these systems use bursts of light from your pop-up flash or infrared (IR) signals. This is more akin to your TV remote control. Such transmissions can be inconsistent as they require line-of-sight and can be affected by other light sources. The range is also limited to about 30 feet.
UPDATE September 14, 2012: Joe McNally recently created a video demonstrating a test using only the Nikon D800′s pop-up flash in bright sunlight and was able to trigger a SB-900 from 100 feet away! That was impressive. If you have two flashes to fire and can’t do perfect line-of-sight, you can expect that distance to be decreased.
When you’re indoors, you don’t really need line-of-sight as these signals will bounce off the walls and ceiling. If you’re outdoors, however, the transmitting part of the camera and the receiver on the flash really need to see each other. This can be limiting as you might turn you camera to shoot in portrait orientation and then lose the connection to your flash.
What’s worse, bright sunlight can effectively wash-out the pop-up flash or IR signal. You may have line-of-sight but will find your flash simply doesn’t fire or fires inconsistently.
Another disadvantage that’s far less discussed is that your camera’s pop-up flash can quickly overheat. Even when it’s not set to contribute real light to scene, my pop-up flash on the Canon 7D forces my camera to report “Busy” while it cools down. It prevents me from taking another photo for 10 to 20 seconds at a time.
This is especially frustrating as I’m not asking the pop-up flash to fire at full strength. My external flash units have no issue and recycle quickly. They sit there idle as I miss shot after shot of my kids. No one told me that the pop-up flash can overheat like that, it’s something I had to discover on my own.
For all these reasons, radio-based triggering is preferred which is why Canon released it’s latest Speedlite (600EX-RT) with a radio trigger. It’s not the most affordable option but I wasmbuilding out a dream setup, I’d own three or four of those and be all set. Given a $1200 to $1800 outlay on flash units is not realistic, we must proceed with the alternatives.
Now that Canon has a radio-based alternative, you can find articles that highlight the weakness of its own optical sytem. Canon makes these points in a March 2012 article but they also apply to Nikon’s optical system as well:
Limits with the current “optical” wireless flash method
Perhaps the easiest way to begin this is to re-visit the inherent limits of optical-based wireless flash triggering. While the current optical-based system is an incredible piece of technology (Canon had the industry’s first truly wireless system for off-camera flash that allowed full TTL exposure control of up to three groups of flashes, when it launched Wireless E-TTL with the Speedlite 550EX and EOS 3 SLR camera, back in 1998), it has several important limitations that photographers have had to be cognizant of:
- Distance limitations
Since current “optical” wireless E-TTL relies on a series of rapid pre-flashes to trigger off-camera slave units, these pulses of light have to be relative weak in strength to achieve their extremely rapid duration and avoid perceptible time-lag. Weak pre-flashes limit the effective distance slave units can be from the camera/master unit to less than 30 or 40 feet in most instances; in some cases, they have to be much closer than that.
- Positioning limitations for slave flashes
The master unit (either a compatible on-camera flash, or the current Speedlite Transmitter ST-E2), puts out pre-flash illumination that covers about the same angle as you’d see from a full-frame camera with a 24mm wide-angle lens mounted. In other words, if slave units are positioned well to the side of the camera, it’s entirely possible they’ll see even weaker pre-flash signals, or possibly none at all. This makes it difficult, for instance, to position off-camera flashes behind the photographer.
- Line-of-sight requirement
Directly related to the positioning limitation above, slave units with optical wireless E-TTL require a clean and direct line of sight to the master unit. If they’re positioned behind objects or people in a scene, and the master unit’s pre-flashes aren’t somehow bounced or reflected to the receiver area of the slave units, they won’t fire. Along with distance, this confines wireless E-TTL to situations where users are in fairly contained areas for reliable operation – and limits creative placement of lights, especially for illuminating backgrounds, as accent lights, and so on.
- Difficulties in areas with bright ambient light
Since the sequence of pre-flashes from the master unit to slave units in an optical Wireless E-TTL system has to use very brief, weak but rapid pulses of strobe illumination, when working outdoors in daylight, photographers are up against some strong competition – the sun. If one or more slave units are positioned so that they’re receiving direct sunlight on their face, the optical wireless sensor may be effectively blinded and not even see the pre-flashes fired by the master unit. Shading the front face of the slave units, and/or working with the master flash much closer to them, sometimes helps. Regardless, working with Wireless E-TTL in bright sunlight, up to now, hasn’t always been a so-called “slam dunk” – even though it is compatible with high-speed flash sync, allowing very fast shutter speeds and flash to co-exist, to tame sunlight exposure.
For reference, the following Canon camera bodies have a built-in flash trigger:
No, it’s not included in the new 5D Mark III as it lacks a pop-up flash. And no, the 5D Mark III does not include any radio-trigger to command the 600EX-RT Speedlite. Learn more in my post about the 600EX-RT.
The compatible Canon cameras can remotely trigger the following Speedlites models:
- 230EX II
- 320EX II
- 430EX & 430EX II
- 580EX II & 580EX II
Yes, the Canon 7D, 60D and T3i can trigger the new 630EX-RT as it supports both optical and radio-based triggering (you just can’t do both at the same time). To learn more about Canon’s optical system, read the Canon article titled “Speedlite Tip Series, Part 3: Wireless Flash Primer“.
For Nikon, the following camera bodies have a built-in flash trigger (more models work with Nikon CLS but they require an attached speedlight):
- D300 & D300S
- D70s & D70
And they can remotely trigger the following Nikon Speedlights:
Option 2: Flash-to-Flash Wireless Trigger
If your camera does not have built-in flash triggering (e.g. Canon 2i, EOS 5D Mark II or an early Nikon), you may still own modern flashes that can communicate with one another. This creates the opportunity to use an on-camera flash as the wireless trigger for other flashes. This is still an optical system but this time the communication is sent via infrared instead of the pop-up flash.
This is unfortunately an expensive option as you pretty much have an on-camera flash unit being used solely as a transmitter unless you plan to bounce the on-camera flash. It’s made worse for Canon owners as only the top-end Speedlites (500 and 600 series) can be “Master” flashes.
For Nikon, there are many flash units that can be the “Commander” of “Remote” flashes in the wireless setup, these include the SB-400 (very limited), SB-700, SB-800, SB-900 and SB-910.
UPDATE September 14, 2012: Joe McNally’s video also demonstrated a test using a SB-900 on a Nikon D800 in bright sunlight and he was able to trigger another SB-900 from 200 feet away! The on-camera SB900 had to be zoomed to 200mm to give it some assistance. That was also quite impressive. Again, if you have two flashes to fire and can’t do perfect line-of-sight, you can expect that distance to be decreased.
To save a bit of money, Canon and Nikon also offer a wireless flash trigger to put on your camera so you can avoid buying a full flash-unit. These special transmitters are still optical as they also make use of infrared (IR) signals.
If you’re planning to take advantage of the new radio-based triggering included in the 600EX-RT, Canon has released a dedicated transmitter called the ST-E3-RT (shown above) which will set you back US$320.
UPDATE September 14, 2012: In the same Joe McNally video mentioned above, he tested the SU-800 on a Nikon D800 in bright sunlight and was able to trigger another SB-900 from only 65 feet away. That was less impressive for sure.
Option 3: TTL Cable + Flash-to-Flash Wireless Trigger
One of the simplest and more affordable options for moving a single camera off-camera is to use a special cable that effectively moves your on-camera flash shoe to another location. This is known as an TTL cable as it offers 100% fidelity in the communications between the camera and flash. The cable simulates the flash sitting on the camera (it literally doesn’t know it’s off the camera).
TTL cables come in various lengths and they’re either straight or coiled. Unless you plan to limit your off-camera use to an arm’s length, DO NOT buy a coiled cable. They might say they’re 6 feet long but when coiled it’s looks like 2 feet. If you pull hard enough it will catapult your off-camera flash to the ground!
Don’t feel compelled to buy a name-brand cable by your camera brand either. There’s plenty of inexpensive alternatives that can be had for 1/10th the price and there’s some DIY options for extending cables with sample RJ-45 wires. You can also look at OCF Gear as it’s recommended by Syl Arena, a Canon Speedlite (watch his recent workshop). B&H sells a variety of long cables as well such as this 33′ Vello E-TTL cable for US$50.
So far, this isn’t yet a wireless option. It becomes a wireless option once you introduce more flashes to this setup and your main flash unit is one that can act as a master/commander (as described in Option 2). You attach the master flash to the TTL cable and then have it remotely control the others in your setup (see Option 2 for details).
Option 4: Sync Cable + Optical Slave Trigger
If you don’t have newer flashes that can speak to each other or you’d like to buy inexpensive third-party manual flashes, there is another option that’s similar to Option 3 but it’s can only trigger a flash with manual power settings (i.e. no TTL communication). In this case, when the corded flash is fired, another flash paired with a light sensor (photodetector) sees that and fires at the same time.
These sensors are referred to as Optical Slaver Triggers. In fact, most studio probes have these built in but they’re lacking in speedlights. Luckily you can buy a flash shoe that has an optical sensor built-in (as shown below) and use with with ANY flash of ANY make.
The important thing to note is you can’t use optical triggers with TTL flash metering. The pre-flash that fires as part of TTL communication will “trip” the optical sensor too early. You can still use a TTL cable but you’ll need to have the corded flash set to a manual power setting. I’ve read that even the infrared signal from flash transmitter can fool some optical triggers to fire too early so watch out for that.
Since you don’t need TTL in for this optino, you can optionally skip the TTL cable in favor of a cheaper cable called a “PC Sync Cord” that fits into a “PC Socket”. Check that your camera has a PC Socket of course. You can find many inexpensive flash units that a PC socket but if they lack it, you can buy an inexpensive flash shoe with the socket for about $10 to $30 (see below for the Vello adapter optimized for Canon and Nikon).
Beyond the lack of TTL, the big downside of this option is that you need line of sight to ensure the optical eye sees the burst of light from the corded flash. In bright daylight, it might fail you as it can wash out the light signal. And finally, anyone else’s flash can trigger your optical slave which could be quite annoying in some situations.
Option 5: Radio-Trigger of Manual Flash
If the optical options above don’t appeal to you, you can still go wireless via radio-waves. There are many third-party flash triggers that are radio-based and do a simple function really well – they tell your flash to “fire!”. There’s no tw0-way communication, just the command to flash. Your flash must therefore be on a manual power setting (i.e. no TTL again).
Radio-based triggers are far superior to the optical options as line of sight is not required. Even in bright sunlight the signal will be delivered 10x further (over 300 feet). Since they go through wall, you can tuck your flash in hidden places you’d never think of to pull off really unique and creative shots (e.g. you could illuminate a fireplace from the inside as if the fire was raging).
If you’re just real-estate photography, you could put a flash unit in a distant room to have it light up a dark corner of your photo. There would be no concern about the flash firing and doing so consistently.
For this to function, you put a radio transmitter on your camera’s hot shoe and attach a radio receiver on the flash unit. You’ll need to set the flash power on the flash unit itself as there’s not real communication between the camera and flash units. This can be annoying if you have several flashes in awkward positions (e.g. high on a boom).
It’s recommended that you invest in a light meter to save time calculating the correct exposure and measure relative power from multiple flashes. It still work without a flash meter, you just have to do more trial and error.
This option can be relatively inexpensive but you can spend real money on premium triggers if you like. The most famous and “professional” triggers are considered those by PocketWizard. The most PocketWizard series is the “Plus II” and the new “Plus III” (available March 15, 2012). The new version is cheaper than it’s predecessor but it will still retail for US$140 each. You’ll need one for your camera and one per flash. For a two light setup, that’s a whopping US$420 over and above the cost of your flashes.
When shopping, don’t be confused by the term “transceiver”. It just means as each unit can send and receive the radio signals instead of having a dedicated transmitter and receiver The big benefit of transceivers is you’re not at risk of having getting stuck when your only transmitter breaks (assuming you have more transceivers available).
Luckily there are a number of other companies creating “manual” radio-based flash triggers. There’s too many to list here but many of my friends trust Cactus brand triggers by Harvest One. Most have the “v4” transmitter/receivers but there is a new“v5” line of transceiver that operate in the 2.4 GHz band. Check out the comparative review by Karel Donk (the photo below is from his review).
Cactus v5 units retail for US$60/CAD$100 for a pair and US$35/ CAD$60 for each extra transceiver. A two-light setup will therefore set you back only US$125 / CAD$160. Not bad. If you can’t find Cactus triggers, you can also look at other very inexpensive options like the Yongnuo RF-603.
Option 6: Radio-Trigger with TTL Support
The dream scenario is of course radio-based triggering while maintaining a full TTL communication to your camera. This would replicate all the benefits of Option 1 but without the drawbacks of an optical system.
As mentioned in Option 1, Canon has made a big step recently toward radio-based triggering with the introduction of the 600EX-RT flash and the ST-E3-RT transmitter. This would not be the most affordable option but you could “discount” the flash’s hefty US$630 price tag by the price of a TTL-capable radio trigger you don’t have to buy. For the rest of us, those with an existing investment in flashes, we must look for other options.
TTL communication is camera brand specific and so are the triggers. With such triggers, you can benefit from E-TTL / i-TTL flash metering and full on-camera control of your flashes. Even when you opt to use manual flash power settings, you can control those settings from your camera. That’s a huge benefit.
PocketWizard plays in this arena with a line called “Flex TT5”. Units exist for Canon and for Nikon and they’re certainly not cheap. A Flex TT5 transceiver will set you back about US$220. A two-light setup will therefore run you at least US$660.
Another popular but expensive option is the RadioPopper system. This system is unique as it captures the optical transmissions from Canon and Nikon cameras and sends them via radio waves to the flash. The RadioPopper units on the flashes re-convert the radio waves back to light signals. See the RadioPopper PX review by Ed Zawadski (the photo below is from his review).
RadioPoppers are an interesting system but at US$250 for a transmitter or receiver, a two light setup will run you $750. That’s even more than the PocketWizard with a lot more work to get going. You can’t, for example, move the RadioPopper to other flash units easily as there’s a setup required to stick the unit over the flash’s light sensor.
Luckily there are some Chinese manufacturers making a couple TTL-compatible units. One company called Pixel has two makes, one called “Knight” and one called “King”. From what I understand, the King units are less expensive and run on simple AA batteries vs. a flat battery. The King line only exists for Canon TTL at the moment however.
A Pixel King pair can be found for only US/CAD$150. Sets exist with two receivers for only US/CAD$240. That’s over $400 saved compared to PocketWizard TT5.
UPDATE: One downside of the Pixel King is that it lacks support for ratio-based lighting setups over TTL. You can set relative power of each group (A, B and C) but you can’t simply select “2:1″ for groups “A:B” to get twice as much light from A than B. For me, this is inconvenient but something I can live without given the cost savings over alternatives.
UPDATE May 25, 2012: My full review of the Pixel King E-TTL Flash Trigger is now available.
Bonus Option: Manual Flash Triggering
Although it is a fringe option, I thought it’d be worth pointing out that you can physically trigger any off-camera flash on your own… yes, with your hand. Just find the flash unit’s “Pilot” or test-fire button. This is a cheap and no-tech solution.
Naturally, you can’t react in 1/8000th second but you can certainly do quite a bit if your exposure time is long (e.g. couple seconds or longer). This technique is therefore well suited to night photography.
Not only can you pop-your flash manually, you can do so many times during a single exposure to simulate many flash units. This is often referred to as flash painting.
See my post about a Night Photography for a great video and some examples of my own work using this technique.
After a couple years of using Canon’s built-in optical system (option 1), I longed for a radio-based TTL solution (option 6) if I could afford it.
Turned out that Pixel King was the most logical option for me given the alternatives. So, just a couple weeks ago, I purchased a Pixel King set with one transmitter and two receivers for $238 from a small shop in Montreal (that’s half-priced compared to Henrys so do shop around). So far, they work as advertised.
UPDATE May 25, 2012: My full Pixel King review is now available.
In the end, what do you think of the options as I’ve presented them? What have you done or might you do and why?
- March 15, 2012: Adorama posted an article, “The Golden Age of Wireless Photo Flash“