Review – Canon Speedlite 600EX-RT

Review – Canon Speedlite 600EX-RT
By: Justin VanLeeuwen | Twitter
Discuss the Canon Speedlite 600EX-RT

Let's be honest, Canon hasn't always been known for their innovative flash technology. Sure, the speedlights worked, and there was a system of sorts to remotely trigger them, but they truly paled in comparison to Nikon's “CLS” offerings. As a Canon shooter, you could put up with a spotty infra-red control system that required line-of-sight and barely worked outdoors, or invest heavily in third-party radio triggers like Pocket Wizards. When I was shooting 580EXII's, just a year ago, I knew that each flash purchase meant a Pocket Wizard purchase too, adding a few hundred dollars to the purchase price just to make it work reliably for my needs. Even then, nothing was guaranteed; once you're dealing with the flash, a PC sync cable and the remote, you have multiple levels of failure. “Why didn't that flash pop? Is it the speedlight’s batteries? Is the cable attached? Is the cable working? Is the trigger working? Are the trigger batteries dead?” So many variables can really be a downer on a shoot, especially if you're working fast. To boot, once you put the speedlight into a light modifier like a Westcott Apollo softbox, you'd lose line-of-sight (which the infra-red system relied on), thus losing any level of remote control over the light output. You'd have to go back to the flash every time, manually adjust it, and try again.

Pocket Wizard released what I had hoped to be a saving grace to this: the MiniTT1 & FlexTT5 remote system, promising wireless TTL control of the flashes (TTL, for those who don't know, is “Through The Lens” flash metering, where the camera automatically adjusts the speedlight’s level for an ideal output). But it wasn't to be. The radio-frequency interference from the 580exII severely crippled the range of the PW's (I was pissed, weren't these designed SPECIFICALLY for these flashes? Who's beta testing this stuff?). So now I've got a few thousand dollars of flashes and triggers, and none of them really do what they're supposed to do, or more accurately, what I need them to do. Frustrating is an understatement, and I end up buying Lumopro's excellent LP160s. “dummy” flashes with manual-only settings for less than half the price of a 580exII. They at least offered optical triggering, which means they'll “pop” when another flash does – “something Canon has never seen much value in, it would seem.

Everything was a compromise, a trade-off, and often a futile effort. Canon released the 7D which offered speedlight control with its pop-up flash; that was cool, it worked indoors well enough. But I don't always get to choose where I work, and my long term goal was to shoot full frame, so there's another compromise; no pop up flashes on the 5D series. Would I have been better off just switching to Nikon? Their CLS system offered optical triggers and control from the base that was consistent and worked.

Enter the Canon 600EX-RT
I'm not going to say radio transmission technology is revolutionary, it's been around for a hundred years, but integrating it into a flash system has been a revelation for my work.

Selling off my 580exIIs wasn't easy. Their drop in price meant I was selling two flashes to one 600ex-RT purchase. But this is about work and the ability to dynamically change your flash settings without leaving the camera. It meant I could have a flash inside a softbox and it would trigger without wiggling a cable, I could change the setting from TTL to manual from the commander unit. Sold. Done. Let's do this.

For this new “RT” system to work for you, you'll currently need either two 600EX-RTs (one to act as a Master/Commander unit) or the ST-E3-RT transmitter. I rarely, if ever, shoot with a flash in the hotshoe of my camera, so I picked up the ST-E3-RT which has all the same control functions as having a 600EX-RT, except, obviously, it's not a speedlight.

A flash's menu system can be quite daunting, and to the unfamiliar, many of the symbols and functions are a mystery. More than almost any other piece of gear, I highly suggest you R.T.F.M and play around extensively with the various features of any speedlight you buy. For quick reference, I keep a PDF copy of the instructions on my phone at all times.

I've always found Canon's flashes to be more aesthetically pleasing than Nikons; a bit more rounded at the edges and all-around a better design. The Canon 600EX-RT is larger and heavier than the 580EXII, Canon's previous flagship flash, which I will never suffer again. A metal foot is necessary to hold the weight (add 4AA batteries to make it go, obviously), and it includes a slide-lock clamp to hold the foot in place on your hotshoe or cold-shoe of choice. The clamp has rubber around it, as does the battery compartment door, so this flash is considered weather-sealed for all your rainy-day flash needs. There is a rubberized button to “unlock” and swivel the flash head at the top that I find rigged and firm, but not stubborn, to move and lock the flash head in the desired position. Rubberized plug covers also adorn the side where you'll find the PC sync cord port (in case you still wanted to use your Pocket Wizard or other trigger system), the external power supply port and the little metal screw port that I've never seen anyone use…

There are a few new buttons which I'll get into in a bit, including the wireless button and a new “lock” feature in-between off and on; this locks the speedlight functions so you don't inadvertently change them when handling the flash.

Like other canon flashes, it has a pull out catch-light panel to help those shooting on-camera flash with a little fill if aimed straight up, it also has a pull out wide-angle diffuser to help expand the flash range to 14mm.

The Canon 600EX-RT comes with a few new accessories. Included is the standard Canon flash “foot” to help it stand on shelves and such. There's also a secondary pouch (with a tiny clip so you can fasten it to the flash pouch) that contains a clear plastic cap that acts as a filter holder for two included specially shaped colour gels. I find this to be an awkward solution; if you've seen how Nikon stores all these same parts for its SB910 you'll wish Canon had integrated it better.

Functions & Features
Like all my reviews, I don't intend on technically measuring flash pulses or light output, recycle times using different batteries and comparing the results; this review is from a real-world use of the product.

The Canon 600EX-RT does expand the telephoto range of the flash to 200mm – up from 105mm in the 580exII -“giving you better coverage when shooting with a telephoto lens, or a more controlled beam of light if you're using the zoom function creatively. The 600EX-RT also retains the infra-red based TTL technology making it compatible with other Canon flashes that share a master/slave function. The 600EX-RT can, in itself, act as a master or slave (secondary) flash in a multiple light setup. A new button has been added, a little “Z” shaped arrow that turns on the single most significant reason to purchase this speedlight: the Wireless Button.

After turning your flash on, it's a simple matter of pressing the wireless button once to set the flash to Master (in order to control other Canon 600EX-RTs around), a second press sets it to slave, so it can be controlled by a Master 600EX-RT or a ST-E3-RT. A third and fourth push of the button put you in the old-fashioned IR control mode which still sucks but if you have older speedlights, then you can at least still use them this way.

The 600EX-RT supports E-TTL, Manual control in 1/3rd stop intervals as low as 1/128th power, “Multi” which allows you to fire multiple flashes at requested intervals within a pre-set amount of time, “EXT. A” and “EXT. M” which give the flash control of the metering (instead of “Through The Lens” it's basically through the flash).

The included filter holder and full CTO (colour temperature orange) gels let you match your flash’s colour output to tungsten light sources. These are specially cut to fit the whole flash head, and they wrap slightly under it to a sensor which automatically detects the colour and sets that to white in camera, if you're using the auto white balance (you can choose to turn this off too). While this is a handy feature, at the time of writing this review, you cannot purchase additional gels other than the two. Currently, I buy large sheets of colour gels (about $5 for a 24″x24″ sheet) and cut them myself, I can pick almost any colour imaginable. $19.95 for official replacements just for the “special shape” of these gels is way overpriced, not to mention sorely inadequate in selection. I actually wish Canon made a special die-cut or scissor I could buy to cut out my own gels, and build on the two colour corrections with other common gels like green and blue. Nonetheless, it's a nice additional feature to help balance the colour of light under certain situations.

Setting up a 600EX-RT is incredibly simple. I opted to turn on the optional “beep” function so I know when the flash is recycled and ready; the sound also translates over to the ST-E3-RT transmitter to let me know the flashes are connected wirelessly. Flip the switch to “On”, press the wireless button twice to enter slave mode, and set your group, A-D.

There is a restriction on the number of flash units you can control within these five groups using the radio transmitter, though I haven't met many photographers with up to, let alone more than, 15 speedlights (that's about $7,500 in lights).

Another restriction is on cameras released before 2012. If you don't own a 5DMK3, a 6D, or a 1DX, you are limited by the number of groups you can control and how you can control them. One of the most versatile control functions of the 600EX-RT is that you can independently manage the five different groups, setting them to shoot manually, E-TTL, or EXT-A, in a mix-and match setup to suit your needs. With the older cameras, you're limited to three groups and ratio control only. This was pretty disappointing when I first set it up on my 5DMKII, and I was quick to upgrade to a 5DMKIII to take full advantage of the expanded feature set.

Once your flash groups are set up you can position the flashes in your light modifier (or modifiers) of preference. Let me use a basic three light setup as an example:

I've set up 3 600EX-RTs all controlled by a ST-E3-RT transmitter. The 600EX-RT in the forward 28″ Apollo softbox is set to Group A, and the two rear lights in Westcott Apollo strips with grids are set to Group B (I could have set one to C but I want these to be equal in power at all times). All of these lights are contained within the soft boxes and it would have been difficult, if not impossible, to trigger them without radio.

My first step is to get my two rear lights properly positioned and then set to the flash power setting I want. Since I want these to be consistent, and the camera may have a hard time reading the scene with rim lights, I've set Group B to Manual on my ST-E3-RT. I can turn the various groups on and off via the transmitter, so leaving group A off I can experiment with different manual power levels until I find one that suits the look I'm going for. With those set up, I can then turn my A channel back on and it will automatically fill in via E-TTL. I can adjust this on the transmitter or the camera body, by adjusting the exposure bias to the left or right to taste. Depending on my position relative to the subject, the Group A flash will vary and this is okay, I might prefer one look over another. Of course, if I wanted, I could set group A to manual for a consistent exposure.

Add or take away lights as you like; once they're set-up you can adjust their power outputs from where you stand, up to 30m (98.4 feet) away, well within the range of almost all of my shoots.

Another practical use of the mixed lighting is with something like the Orbis ring-flash. Ring flashes are great for use on-camera when you want to eliminate or reduce shadows on your subject, but moving around can easily force them to become too bright or too dark based on your light-to-subject distance. For the next shoot, I had a 600EX-RT in the Orbis ring-flash set to TTL, and a second 600EX-RT with a red gel bouncing off a wall just above my subject’s head. While the subject and wall flash were of consistent distance to each other, the camera (and me) with the ring-flash attached were constantly changing distances. Shooting E-TTL helped keep the shoot moving along without any fussing over the settings. Note: the Orbis is currently the only speedlight based ring light that will fit the larger head of the 600EX-RT.

Who's it for?
This flash pretty much does it all, and while it's clearly aimed at the pro market, beginners will also benefit from the wireless freedom it presents. Though many people starting out with a flash rarely take it off the camera -“ I do hope they will in time.

Event shooters including wedding photographers will find good use of the Canon 600EX-RT while on the job. Being able to use this same flash off camera can help while covering the dance-floor and you can dynamically adjust your settings depending on your position in the room relative to the light.

Editorial photographers and photojournalists will certainly want this in their kit. The ease and speed to set-up and adjust will pay for itself just as quickly as those shoots last. In the case of media scrums, if there are other 600EX-RTs in the room, you can change the Radio ID through 10,000 different frequencies as well as triggering units among 15 channels, making it unlikely for your flash to interfere with someone else’s shot.

Professional portrait and corporate photographers will appreciate the power to size ratio. While not replacing the pure power output of a studio strobe, many will augment their lighting setups with a smaller flash. The sync port at the side allows any number of compatible trigger systems to take advantage of the flash. You will lose the fine control you get with the radio, but having the option to still use the light is valuable. And, in other instances, a few speedlights may be all they need to quickly and efficiently complete the shoot.

I often use speedlights in my interior photography. A small boost of light to lessen the dynamic range can greatly enhance the feel of a location. I can discretely position a number of speedlights and remotely control all of them manually for the perfect exposure.

Sports shooters will take advantage of the short flash duration for stopping action, and, while I haven't experimented with it myself, truly remarkable things can be accomplished using the “multi” setting and some motion.

Have a Canon camera? Need more light? Buy this flash. Flash photography may not be easy to master, but luckily for you, there are so many incredible resources on the internet to help you learn how to use and modify your flash to get the look you're trying to achieve. All I ever asked for was a flash that actually responded to my needs, making me feel comfortable and confident on a shoot; just like the 600EX-RT does.

The only thing the 600EX-RT doesn't do is set itself up in my flash modifiers and move itself around on the light stand. Really, I did mention that shooting with the 600EX-RT was a revelation. Imagine all the frustration and misfires you had with previous flashes, all the time spent fine-tuning the manual output settings, or taking apart your softbox just to access the flash, all that frustration and anger gone, and in its place? Freedom.

Undoubtedly, Canon will soon update the more affordable 430EXII with the new “RT” technology, which would open up a lot of entry-level shooters to the market. That would be my suggestion for someone getting into camera flash, but knowing the limitations and additional expenses that come along with expanding your lighting arsenal, I really have to say the 600EX-RT is the flash to buy for anyone interested in variable control of their flashes. If you're on a budget and not concerned about E-TTL options, I still love my Lumopro LP160's; they just work. But if you want versatility and control, ease of use and frustration free flash lighting, there's no flash on the market that outshines the 600EX-RT.

Purchase Options:


  • ETTL “automatic” flash system
  • Wireless Radio control
  • Backwards compatible with previous Canon flash models
  • Easy to navigate button & menu system


  • Most expensive speedlight you can buy
  • No other Radio models (currently) available
  • No other 1st party flash gels (currently) available