Jim Heine Photography – Lehigh Valley, Philadelphia, and Destination Wedding & Documentary Portrait Photographer » upbeat, modern, creative photojournalism wedding photographer and documentary day in the life family photography

Canon 600EX-RT Radio Flash Review

Disclaimer: This review is intended for photographers and photography gear nerds.  If you’re looking for beautiful wedding or engagement photos, continue down the blog.:)


Radio trigger technology for flash just came into being a few short years ago and really revolutionized the photography industry.  Before then, most wedding photographers kept their flashes on their cameras or had a corded one light system.   Radio freed us of the cords and allowed us to use flashes quickly off-camera in all conditions.

Up to now I have used most of the popular radio trigger technologies extensively, including PocketWizard (Plus system), RadioPoppers (PX and JrX), and CyberSyncs.  They all have their pros and cons and applications that each excels at.  There has been one consistent problem across the board for all the triggers – they have times when they’re unreliable.  No, it’s not all the time, but sometimes the triggers just don’t work or work sporadically.  Often times the problem results from a flaky cord, connection, or interference.   Problems like these are notoriously hard to troubleshoot.  A flash might work every other shot or quit working after 5 shots.  You just never know.

Last year I started to get fed up.  It is extremely embarrassing when you’re in front of a client and your equipment malfunctions or works inconsistently.  This is especially true when you’re on an extremely tight schedule and under pressure, such as at a wedding.  There’s nothing worse than 15+ anxious bridal party members waiting for you to trouble-shoot your equipment.

So last year I switched to using Einstein flashes, Vagabond Minis, Cybersyncs, and the CyberCommander.  The Einsteins worked much more reliably, I think primarily due to less cords.  The Einsteins have a transmitter that simply plugs directly into the unit.  One less thing to go wrong.  The Einstein system is not perfect, but it’s better than any system I’ve used.  They’re a bit heavy, but I have all the features I want, including plenty of flash power/range and remote power control.

Enter Canon with the 600EX-RT.  When Canon first announced the new flash system, I had a “meh” response.  They were expensive and didn’t offer much in the way of upgrades over the 580EX flashes.  I ordered one 600EX-RT, just out of curiosity from a retailer with a very good return policy.  After minutes of getting the flash in my hands, I got two more.  I was quite excited by the all-in-one nature of the flash.  No more separate radio triggers, no more faulty cords, no more troubleshooting connections.  The best thing going for the 600EX-RT is that it should be a very reliable and foolproof system to use.

New Features

So, it’s maybe a little disappointing that the 600EX flash doesn’t have much in the way of new functional features.  The only real upgrade is to the zoom.  It now goes from 20mm-200mm compared to 24mm-105mm on the 580EXII.  A nice upgrade, but it won’t make a huge difference for most photographers.  Power output and recycle time is identical to the 580EXII.  The 600EX-RT is slightly taller than the 580EXII, but they’re not far apart.

The flash does have some other improvements, however.  One huge difference is the usability of the menu system…and you’ll need it to utilize all the neat features of the flash.  Every other professional Canon flash before the 600EX had an absolutely atrocious menu system.  Previously you had to hold in buttons to get to certain features and had to cycle through multiple options before you got to the setting you wanted.  One key feature I enjoyed on the 5d Mark II was that it added a menu option in camera to adjust flash settings.  Well now it’s equally easy to use the actual flash menu to change settings.

Now we have a MODE button that cycles through the different modes – ETTL, Manual, Group, Multiple, ExtA, ExtM.  There is also a wireless mode button that cycles between No Wireless, Radio Master, Radio Slave, and Optical.  On the LCD we see up to four menu options on the bottom.  There are four corresponding buttons for those options.  It’s not perfect, but it’s fairly intuitive.

There’s also a gel holder.  Hmm…  seems like a huge gimmick.  I’ll get into this later.

The biggest addition is the radio trigger system.  We’ll be focusing on this and its features.

Radio Modes

The reason to get this flash is the radio system.  And with it comes a few new options plus a brand new mode – Group Mode.

ETTL mode.  This will trigger all the flashes to get an automatic exposure.  You can dial in exposure compensation if needed.  Ultimate dummy mode.  There is a note in the manual that states, “radio transmission wireless shooting using E-TTL autoflash is not possible” when using cameras released before 2012.  I’m not sure what this means, as I tested this mode on the 5d Mark II and it seemed to work.  I rarely use all ETTL mode, so I admit I’m not an expert.

Manual mode.  Can set up to three different groups of flashes at manual power settings.  You can control the flash power level remotely for your flashes with a quick button press or two and a flick of the dial.  Awesomeness.  Compatible with the 5d Mark II.

MULTI mode.  I never used this much, but I’m going to try it more this wedding season.  It’ll send multiple flashes during the exposure, like a strobe.

GROUP mode.   This mode is the bread and butter of this flash.  Group mode allows you to control up to 5 separate groups and set each group to either ETTL, Manual, Ext.A, OFF.  You can dial in the exposure compensation or manual power settings and it’ll change the power levels of your slave flashes remotely.  There are some definite creative possibilities available with this mode if you use your imagination.  Sadly this mode is not available for any Canon cameras models older than 2012.  So it just works on the 5d Mark III and 1dx for now.

The Good

New Menu System.  It’s not perfect, but it’s much better than previous flashes.  It’s much more intuitive to use.  They also made it fairly easy to toggle if your master flash will fire or not.  You literally just have to tap two buttons.  This is a feature I use EXTENSIVELY.  You can see where it is on the “MENU 2″ in the above picture.  With the 5d Mark II, I either had to dig through the on-camera flash menu or turn off the flash (which unfortunately disabled focus assist).  I love how readily available the option is.  If they could add it to the first set of menus, I would be swooning.

Sync on the 5d Mark III (and presumably the 1dx).  All other radio triggers have maxed out a full sync on 5d series cameras around 1/160.  A full power flash on the 600EX with radio can fully sync on the 5d Mark III at 1/200 sec.  That gives us 1/3 more stop to overpower the sun or slow down any ambient-lit subject movement.  CyberSyncs and RadioPopper JrX sync at 1/160 on my 5d Mark III.

High Speed Sync up to 1/8000.  I never use HSS, but it’s there and I tested it up to 1/8000 on the 5d Mark III.  HSS doesn’t appear to work when radio is used on the 5d Mark II or camera models released before 2012.

Ability to have 2 or more master flashes with different settings being used concurrently.   This is pretty awesome for those who work with another Canon shooter.  Each shooter can control the settings and power levels of the slave flashes.  It’ll automatically and instantly flip back and forth based on who triggers the flash.  Canon really got the remote power control system down.

Retains your settings when you turn off the flash or change batteries.

Memory setting.  You can program your 600EX to remember a certain set of settings.  So say you have a typical reception scheme.  You can set group A to ETTL, group B to 1/32 manual power, group C to 1/16 manual power, etc.  You can store these settings in memory, so that you’ll be ready to roll when the schedule’s running tight.  Just raise the light stands and go.  I don’t know how many studio photographers would use the 600EX-RT, but I could see this being useful to save studio lighting settings.

LCD colors.  The LCD changes colors depending if the flash is running as a master or slave.  Brilliant.

Optical wireless mode works with the legacy Canon flash wireless system.  I highly doubt I’ll use this feature, but some people probably will.

Sync Light.  There’s a green (or red) light on the back of the flash indicating if you have a radio sync with other 600EX-RT flashes in the area.  This is great to tell if you’re out of radio range or if your other flashes are turned on.

One set of batteries.  No extra or separate batteries for radio triggers!  It’s all self-contained.  You’ll only need AAs.

Can trigger the shutter of a remote camera using the radio system as long as you have the applicable cord.

Uses the same battery packs and has the same connections as the 580EXII.  I have battery pack, so this is a good thing.  The flash also retains a standard PC-sync port.

Neither Good, Nor Bad

Range.  I think range could have been slightly better.  It’s not bad, but it’s not nearly as good as CyberSyncs (only other system I tested for this review).  I did two tests for range.  My first test turned out much better than my second test.  I’m not sure why this was.  It was the same location, different days.  On the second test I raised the flash to around 10 feet, whereas it was closer to 5’ on the first test.  Not sure if that made the difference.  I’m supplying the far less optimistic numbers from my second test.

  • 30 meters – Flawless operation
  • 40 meters – Occasionally lost sync and the test button occasionally stopped working, but slave flash was reliable when triggered for a photo
  • 50 meters  – Sync and test button were intermittent, occasionally took an extra frame or few seconds to remotely adjust flash power, but the system had good reliability when triggering the slave for a photo.
  • 60 meters  – Reliability dropped off fairly dramatically.  Everything worked about 50% of the time.

I’d like to test the range in different environments.  It’ll also be interesting to see how it works at venues where there may be significant radio interference.  My personal conclusion was that even in very large ballrooms, I should be fine.  It seems the 600EX is sending a lot of information back and forth to keep synced and adjust power levels.  Even when the sync light is intermittent, the camera can often trigger the slave flash for a photo.  The 600EX just doesn’t have the range of some simpler triggers.  For reference, CyberSyncs were 100% reliable to exactly 100 meters.  Then reliability dropped off very, very drastically.  I didn’t try the CyberCommander.  I know the CyberCommander has a limited distance due to the increased bandwidth needed.  The 600EX-RT probably has a similar problem.

No real upgrades to the actual flash from the 580EXII.  The 600EX really feels like a 580EXII when you use it.  Recycle time and flash power are identical.  The only differences are the zoom range was extended and the zoom operates quieter.  I guess if it aint broke…?

Setting power levels remotely.  While the ability to set slave power levels remotely is a huge plus and it’s fairly easy, this feature isn’t quite as easy as with the CyberCommander or JrX knobs.

The Bad

Sync on older cameras (such as 5d Mark II) is a problem.  Oh, this is almost a deal killer.  It’s bad.  With my testing, to FULLY sync a full power slave flash with a 5d Mark II using the radio features of the 600EX, you have to set your shutter to 1/100(!) or slower.   I noticed no difference between 1/80 and 1/100.  1/125 isn’t bad, but by 1/160 a shadow on the bottom of the frame is quite noticeable.  So 1/125 is probably usable and 1/160 in some situations, but know the shutter shadow will be there.  You’re going to have to keep at 1/100 if you’re shooting on a seamless or in any critical applications.  You may want to keep a set of third party radio triggers if you still shoot with an older camera and need more sync speed.  Keep in mind, these test photos aren’t perfect.  They were just for personal use before I knew I was writing the review.  But the differences are MUCH more noticeable at a larger size and especially when you flip back and forth.  I haven’t tested any other cameras, except for two 5d Mark IIs.

Some modes and features, such as group mode, are unavailable on all cameras except the 5d Mark III and 1dx.

No triggers to use with off-brand or legacy flashes.  Canon hasn’t made (and probably won’t make) any radio receivers to trigger studio strobes or other flashes.  This also means you can’t use a light meter with the 600EX-RT.  You CAN hook up a Pocketwizard Plus, RadioPopper JrX, or CyberSync trigger to the sync port of your camera and then trigger slaves with a concurrent system if you want.  Not ideal.

No trigger for Nikon shooters.  I haven’t tested the ST-E3-RT or 600EX with Nikon cameras.  I’m guessing that even if they do work, all the features won’t be there.  I’m fairly confident we won’t get an easy way to share our lights with Nikon second shooters at any point.

Slightly harder to manually change power levels on the back of a slave flash in manual mode.  This can make a difference if you use an Apollo softbox or have the light very high on a stand.   But in those situations, why not use remote control from the master flash?  To adjust manual power on the 580EXII, you simply have to find the dial, hit the button, turn the dial as many clicks as you want and you’re done.  With the 600EX you have to hit one of the menu options before turning the dial.  Since there are more buttons up there, it’s SLIGHTLY harder to find.  Overall, this issue is small potatoes, but worth noting for those that like to manually set the flash power levels on their slaves on the actual flash and not set levels remotely.

ETTL.  I don’t know why, but Canon ETTL has historically always gotten it wrong when you bounce.  You still have to dial in +2/3 to +1 stop exposure compensation on average.  It’s fine since I’m used to it.

ST-E3-RT doesn’t have focus assist.  The ST-E3-RT is basically a 600EX-RT without the flash head and focus assist.  Why didn’t canon keep focus assist on this?  The 5d Mark III has good autofocus, but I still use focus assist when the sun starts setting.  Most of my shooting outside is around dusk or after dark, so I’ll be skipping the ST-E3-RT.  Bummer.

The menu system is much better than the 580EX, but that isn’t saying much.  The menu system could be improved.  It seems designed by engineers rather than photographers.  The menu is usable and it works fairly well, but gosh, haven’t they ever used an apple product in Japan?

Second curtain sync doesn’t work in radio mode.

The gel holder is a joke.   Canon only includes two gels.  One gel is similar to full CTO (just eye-balling) and one is about 1/8 or 1/16 CTO from what I can tell.  There’s barely any density on the lighter gel and it’s worthless since hot shoe flashes don’t have perfect color balance across the power spectrum to begin with.  They should have include a full CTO gel, a 1/2 CTO gel, plus at least a fluorescent green gel.  2012 and newer model cameras are supposed to sense a gel there and adjust the auto white balance closer to tungsten.  I haven’t tested it extensively.  It might work, but it’s much more of a pain than the custom Velcro gels I’ve been using for years.  I shoot RAW, so AWB isn’t a huge issue.  I should note that if you put your own gel on, you ideally have to disable the gel compensation feature entirely if you want the AWB to work properly.  Too much effort…  One other problem I noticed is the gel doesn’t like to lay flat over the flash head in the holder.  So you likely will get light leaks of ungelled flash color off to the sides.  My velcro gels are much easier to use.  See below.

Cost.  There are many other radio and flash options out there and some have similar features for less cost.  I believe the 600EX-RT will make it up in reliability, but it’s still an issue.


For the right photographers, the 600EX-RT will be a wonderful tool.  You get remote flash power control, flexibility, total creative control, all in a convenient and compact package.  No more fiddling with wires, connections, and radio triggers.  This system is built for speed, portability, and reliability on the go.

For those who don’t own a 5d Mark III, 1dx, or newer Canon camera, this flash system is wayyy less cool.   I haven’t done extensive testing on different camera models, but the sync speed is probably going to be a problem for many older cameras.  You also won’t have access to all the snazzy modes and features.  Price will be a major concern for many.  Let’s face it – even a fantastic product like the Einstein is cheaper than the 600EX-RT.  And for about $140 you can buy both a powerful manual hot shoe flash and a (fairly) reliable radio trigger.  But if you have to work fast, you’ll appreciate the 600EX-RTs.

I personally have some creative ideas on how to use the new 600EX-RT in my wedding photography this year and I hope we, photographers, can use new tools like this to further our craft.

  • Jon-Mark - 04/07/2012 - 3:38 pm

    Hey Jim, good review! Very thorough! I’ve read varying reports saying that apparently only certain 5D series cameras can sync at 1/200, others only at 1/160. I use OCF a LOT, and in my experience I never have troubles syncing at 1/200 with my 5D2. Seems random I know. If there is any discrepancy, it has never shown up to my nitpicking eye.

  • David Bell - 04/14/2012 - 7:30 am

    Very good write up. For now I think I will stick with Pocket Wizards (Mini & Flex) but switch from using a 580EX to 430EX ii flashguns which will offer the best range. This new flashgun aint cheap either!

  • Todd - 04/24/2012 - 11:26 am

    The gel holders could have been better. They are not easily used, as you describe. Plus, the gel holders seem fragile, and will not be easily packed with the flash, or stacked with other gel holders

    I believe you are having issues with the gel because you have laid it across the flash head. The Canon gel should lay across the face of the gel holder, and the elongated tab should be situated into the flanges beneath. When tucked into the black flanges, the tab lays across a sensor that is designed to reflect light through, and mirror across, and reflect light back into the sensor. That way, the flash knows what color gel it is. It is a great idea in theory, but not implementation.

    When the gel does lay across the face of the gel holder as designed, it allows some degree of ungelled light through the sides and top of the holder, which makes it unusable in many situations.

    Furthermore, it seems the flash can detect the Canon gels, and will only correct for a Canon gel. I’ve tried other gels, and I get the “!” mark on the flash. It also does not correct the white balance as it does for the Canon gel. I don’t know if it’s measuring thickness, fit, or some sort of coating on the gel.

    Either way, the gel holder is a disappointment for all but casual users under heavy tungsten lighting.

  • enki - 04/26/2012 - 12:20 am

    Could you get the 600ex to link and flash with the 5DMark iii without the Canon – ST-E3-RT Speedlite Transmitter?

    I get no off camera flash joy without a syncord.

    How did you manage off camera flash?

  • Jim - 04/26/2012 - 12:42 am

    Enki,you need to use either a 600EX-RT or ST-E3-RT on the camera to fire an off-camera flash using the canon radio system. Set the on camera flash to master radio mode, then the off camera flash to radio slave mode.

  • KPK - 05/04/2012 - 2:31 am

    Is there a chance to work at the same time with 5D2 and 5D3 with the 600EX-RT on them and remotes ? I try to realize if there is a chance to put the 5D3 in group mode and the 5D2 in normal mode.

  • Jim - 05/04/2012 - 12:10 pm

    Yeah, it’s no problem to use the 600EX-RTs on the 5d2 and 5d3 concurrently. The 5d2s obviously won’t work in the new modes, such as group, but the slaves will switch back and forth seamlessly as if you had multiple 5d3s.

  • Rienz Photoz - 05/28/2012 - 11:49 pm

    Thanks for the nice review, it was very thorough.
    In its defence, Canon clearly stated the 30 meter range limit in their brochures and manual.
    I bought 3 of these babies and they work flawlessly on EOS 7D, including high speed sync, both on camera and off camera. So I am not sure why Canon stated that it wouldn’t in their manual.

  • Paul Kuroda - 06/04/2012 - 3:10 am

    I have been using the Flex TT5’s with 580ex II’s with good luck so far with the AC7 shields, I just purchased around six of these 600ex RT’s.

    The first major problem I noticed was that the master took longer to recycle than all the other slave strobes, even with its’ flash off!

    Also, none of the strobes could fire until that had fully recycled. So at full dump when shooting outdoors I had to wait and miss shots unlike using my previous system as it would still shoot even if the 580exII’s were not fully recycled.

    I am using a Mark IV, but tech support tried it on a 5D Mark III and it had the same delay. I changed my CF #6 to quick recycle, but no change. I’ll check with Canon to see if they can change the CF too and if it will work quicker with the new body.

  • MattVanBIene - 06/06/2012 - 2:52 pm

    Jim, great review and thorough too. I recently took my new 600ex-rt’s out for shoot and they worked great except for one thing. I was getting seemingly random missed shots and I noticed my link light would be green, then go red, then go green, etc. etc. seemingly randomly. I was no more than 50 ft away from the units at times. There were some power lines about 100ft away, but other than that we were in a secluded area with very little interference to my knowledge. Any idea as to why the link would drop and re-connect?

    Thanks for any input!

  • Jim - 06/06/2012 - 2:56 pm

    Not sure Matt. I haven’t had any problems with range so far and probably have shot around 20,000 frames in a variety of situations with them. Make sure your channel is set to auto (default) to get the best range. I had a friend who set it to a specific channel and was getting mediocre to bad range.

  • Jeni - 06/13/2012 - 11:04 pm

    First, thank you so much for this thorough review. I’ve been waiting to get a new flash for a couple of months while waiting for reviews. I shoot 2 5Ds and my 580exii has issues dumping power and misfiring. I’m wondering if I am unable to upgrade camera bodies until year end if I should get the 600 or the 430. I would like the radio feature, but it won’t really be used until I do upgrade. When I do, it will probably be the MKII.

    Thanks again.

  • Jim - 06/14/2012 - 7:50 am

    Jeni – If you’re not upgrading to the 5d3s anytime soon, stick with the 580/430s. The radio sync speed with the 600s is just not that great with pre-2012 cameras.

  • Hawaii Wedding Photographer - 06/24/2012 - 6:54 pm

    I made the switch and what a significant improvement!!

  • Nick - 08/22/2012 - 11:42 am

    Do I really need the Canon ST-E3-RT Speedlite Transmitter for my master / slave reception lighting setup? I’m just thinking about spending the money on an extra 600ex rt rather than the Canon ST-E3-RT Speedlite Transmitter. Does anyone have an opinion?

  • Jim - 08/22/2012 - 11:51 am

    The ST-E3-RT doesn’t have focus assist, which can really be useful at dark receptions. I would go for an extra 600EX if you can afford it

  • Nick - 08/22/2012 - 11:58 am

    Thanks Jim. Would you say the ST-E3-RT is pretty much the 600 ex without the flash?

  • Jim - 08/22/2012 - 12:06 pm

    Yes. ST-E3-RT is the same as the 600EX without the flash or focus assist.

  • Nick - 08/22/2012 - 12:08 pm

    JIM Just what I needed to know. Thanks so much!

  • Allan - 11/23/2012 - 7:00 am

    Hello Jim,

    I have the canon 5D mark ii.
    I have only tested once using two 600 ex flashes, with one hotshoe mounted as the master. I’ve noticed you can’t use groups, but is it possible to fire the hotshoe flash -1 or -2 via the camera’s E-TTL metering system and have the slave set in manual mode?

  • Jim - 12/16/2012 - 3:54 pm

    That is not possible using the Canon radio system Allan. You could use another radio trigger system in addition to Canon’s (cybersync, etc) and fire the manual slave with that. Sorry for my delay in getting back. All the slaves must be in the same mode as the master with a Canon 5d II. What you’re asking is basically what group mode is designed for

  • Wes Craft - 03/13/2013 - 4:25 pm

    Not new to off-camera flash but new to 600 series flashes. The first thing I noticed was that it seems like they fire all or none. If one isn’t recharged do none of them fire? Oddly enough I was using battery packs on all of my flash units, not firing my master at all, in close proximity to my units, and had them all in low power settings 1/16th. It didn’t seem like any of them should’ve had problems recycling and even if one did, I’d hope that the rest of my lights would fire anyway. Thoughts? Anyone else having similar dropped frames/misfires?

  • John Dennaford - 03/22/2013 - 8:41 pm

    Is there anyway to control the off-camera 600ex’s zoom control from the ST-E3-RT?

  • John Dennaford - 03/23/2013 - 6:28 am

    Hi Jim
    This one of best Canon 600EX-RT reviews I’ve seen – and I’ve read many! Thank you for the insight.
    Since posting my previous question, I have found that the 600EX-RT, when acting as a slave flash, can emit a 1Hz LED flash that provides AF assist(ST-E3-RT manual p25)but I agree it would have been better to come from the on-camera transmitter.
    Kind regards, John

  • Jim - 03/23/2013 - 3:22 pm

    John Dennaford, Unfortunately you can’t control the zoom remotely from either the 600EXRT or ST-E3-RT. Hopefully Canon will address this in the next model :)

  • Jim - 03/23/2013 - 3:25 pm

    Not really sure. I know that if one of the flashes doesn’t recycle in time, none of the flashes will fire. Also, quick recycle doesn’t work in radio mode. Occasionally if I walk out of range I have to turn the flashes on and off to re-sync them. Other than that, I rarely get misfires.

  • Lem Lynch - 06/07/2013 - 4:19 pm

    You said: “Can trigger the shutter of a remote camera using the radio system as long as you have the applicable cord.”

    What cord???? How?

  • Jim - 06/08/2013 - 1:31 am

    Lem Lynch, I believe you would need a Canon SR-N3 cable. I have never done it, so you might want to read the manual online just to double check.

  • Jovi - 11/16/2013 - 9:09 am

    Hi, very nice review. I want ask a question that when I try to use 600Ex-rt on my 5D2, and set the mode to AV,and turn on High-Speed Sync. But the max shutter speed is still 1/200, even the it’s very bright. Then the result is the picture over exposure. Do you have the same trouble?

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