Friday, April 13, 2012

Ask Ron: Canon 600EX-RT Radio Wireless and High Speed Sync on Sunny Days

1/400 sec at f/5.6, ISO 200 – Fill Flash via High Speed Sync

After doing my Canon 600EX-RT Wireless Real World Test article several readers have asked me how they perform when being shot wirelessly on sunny days, and a couple people asked about their wireless high speed sync performance for use as a fill flash.

I tried to answer all these questions in one shot above where the sun was setting. I shot directly into the sun with my camera set to 1/400 sec and used an external 600EX-RT on an umbrella as a fill flash via high speed sync. I got the desired lens flare and warm sunset look, but I also got the fill light to keep my subject from being backlit. I also got catch lights in her eyes.

There’s minimal processing on this shot taken from a Canon 5D Mark III that has been processed mostly in Photoshop CS6 Beta and Lightroom 4 from the original RAW which was processed in DPP. It’s not a portfolio shot, but it does prove the point that I can indeed get the fill flash using high speed sync (required at anything over 1/200 sec on this camera). I can also get more ambient light on the background if I want it by simply raising the ISO which I did not want to do for the this shot.

The 600EX-RT’s fired every time in the 58 times I tested this scenario, so they had no trouble with the sun (which should be true of any radio triggered flashes).

I hope that helps those who were interested in this question!

If you have a question for me, feel free to send me a mail with the subject Ask Ron. I can’t promise I’ll answer every question, but you may see your response on the next Ask Ron!

Best wishes,

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Olgierd said...

Any chance you can test new 600ex-rt on the top of Flex TT using older camera than 5D3 (like 5d2 or 7d, using control TL rather instead of Canons WiFi). I'm curious if shielding is improved over 580EX2 and what is max distance with 600EX-RT and PW Flex/Mini TT combo without the RF shield. said...


I'm not sure your test makes much sense because if you have the 600EX-RT, you don't need the Pocket Wizards. The 600EX-RT's don't need the sheild and don't seem to have any interference issues (although I could only go about 95 - 100 feet reliably).

The Pocket Wizard system is not compatible and interchangable with the 600EX-RT from what I understand, so my advice is to either go all 600EX-RT's or go with all 580EX's and the PW.

It makes very little sense to put a 600EX-RT in the pocket wizard system. However, even if you did then it would presumably because you have a mixed flash environment so you'd still have the sock or hard sheilds of the Pocket Wizard system to put around your 600EX-RT if (and probably doesn't) have any problems with interference.

Olgierd said...

Thanks for reply. I'm not trying to mix Canon's wireless with PW. I had 5d2 and 7d and PW Flex/Mini TT combo which I have used in the past with two 580EX. Since I've upgraded 5d2 to 5d3 and know that so far newer camera is not supported by PW firmware yet.
I also lost one of the 580EX and I'm trying to get replacement. Obvious choice is to upgrade to something newer like 600EX-RT. That's why I would like to know if I can use it on Flex TT (use it with PW wireless only) with my other camera (7D which still works with PWs) and to find out if it would work with longer distance than 580EX2 without the shield.
Thanks! said...


Ok, that makes sense. Sadly I can't tell you for sure since I don't own the PW's. It should work at least as good as the 580's but I'd ask PW directly. There's a slight size difference that could be an issue in the shields.

In your case I'd still advise going with the cheaper 580's.


Roberto Farren | Photographer Boston MA said...

Great review.

I had wondered the same thing about PW's (mini and flex) and the new 600ex-rt, and when I spoke to PW they said in would be a couple of months before they got them working with the 600's.

I have a few 580ex2's and a couple of 430ex2's (because they don't need shielding) and had wondered about compatibility, simply for the sake of being able to switch system's gradually, verses simply quitting with one and having to spend around $3000 to replace it. I could do with another flash, but I am now torn between going for the new system or maybe picking up another 430ex2 and TT5.

I presume that Canon have dealt with the HSS issues in the new 600ex that caused some if the 580ex2's to fail the IGBT transistor?

Great review, thanks. Roberto said...


Given your investment I'd say it's probably better to stick with what you have, but yes I'm thinking that Canon worked to resolve the issues PW faced before releasing the 600EX-RT's. I didn't have any problems, but I only did limited testing with the two units I had.


Olgierd said...

Thanks guys for rply. I've hope PW will figure out something rather sooner than later. I got quite some investment in Mini/Flex TT combo (zone controller, AlienBee adapters etc.). I can still control my ABs and 580EX2 when I switch PWs in basic triggering mode with 5d3. Honestly only one reason I still have 7d is because it still works well with PWs in ETTL. Let's hope Mini/Flex combo for Canon won't be wireless system with shortest living span and highest price.

zanadoo said...

As an Habit, Canon develop their own technologies. But at this time, Canon make a mistake. Why ?
1) their system is not compatible with PW or other companies wireless system.
Canon forgot that Photograph have studio light, flashes,... and with PW, their heterogenous systems work perfectly (Elichrom work with PW..)
now, with a speedlite 600EX-RT, it will work with a speedlite 600 !
2) the investment is not a good opportunity for a professionnal photograph. Most of time, he has a or more than speedlite 580ex and with the 600EX, it cannot work
(over 700$ /600EX in comparaison of a 580Ex ~500$)
if i add the cost for a 5DMKIII (the GPS is not compatible with lower 5D MK III)
3)Canon forgot a big problem:the incomes of a photograph decrease and the Canon costs increase (+1000$ for the next 24-70mm f2.8)
a new photograph who want to begin, will spend more money than a photograph with 2-3 years of experience.

Canon should have been compatible with PW and close the door for Nikon. it's like " i'm compatible with the best an most common system of photoraph, not you !"
it will be a very goor opportunity to convince photograph to buy Canon. said...


Thanks for your comment, but remember "all that it is technically possible isn't always legally possible." With patents and radio transmission restrictions, there are going to be non-engineering related limitations.

I seriously doubt that Pocket Wizard wants to see Canon's new flashes being 100% compatible with their products, and if Canon were to do so simply because it is technically possible from an engineering perspective I would fully expect to see them spending a lot of time in court and paying a lot of money to Pocket Wizard, the DOJ, the EU, and more...

On the otherhand, if there were no patent related restrictions, I'm quite certian that Canon would have enjoyed nothing more than to make their new flashes the controller of all things Pocket Wizard precisely for the reasons you describe.

It totally sucks, but that's life.

Mike said...

I'd love to see a 600EX-on-TT5 quick review, simply for the simple fact that I've got 5 TT5s and 5 430IIs (and 2 TT1s) and I am considering switching over (just for simplicity)

I don't want to sell what I have to get all-new this close to the wedding season, and I wouldn't do a full-on upgrade until probably November, but if they worked flawlessly, I could swap out flashes throughout the summer (especially if I kill a flash...)

Tracey Frugoli said...

I am new photographer with a 60D and a Sigma 610DG Super. I am frustrated that I can't get the maximum compatability with it in TTL or eTTL. When I am shooting outdoors and on the fly (either on or off camera) I would like to just have them work together to adjust flash exposure. When I have more time that is another matter. I have a 5D Mark III on order and was thinking of upgrading to a cannon speedlight--specifically the 600EX-RT. Is this the way to go? Can my 600EX-RT be controlled off camera by radio and my sigma as a line of sight slave off camera? I can set the sigma to flash when it sees other flashes I think. Sigma's manual is cryptic and inadequate I have to say. Another reason I have not taken to it. said...


I haven't used the Sigma 610DG Super, but I found the ETTL to be brilliant with the 600EX-RT both via infrared and radio wireless. It was a lot more predictable and reliable than what I saw with the Pocket Wizard Flex/Mini solution - which wasn't too bad either.

You won't be able to use wireless radio and IR at the same time, so you'll need more 600EX's if you want a radio ETTL solution. There's no point in doing the 600EX if you aren't going to use the radio wireless, so you'll need at least two of them. It's an expensive investment, but it sounds like you'll be a lot happier to buy a solution to your current frustration.

Honestly the only gripes I had about 600EX-RT were the insane price and the skimpy bundled gel solution. Performance-wise it was brilliant.

Ron said...


Unfortunately I can't test that for you- perhaps Syl Arena will do that.

What I can tell you is that you'd probably appreciate the lighter load in your bag and fewer batteries. I think you'll also find that IF you use ETTL, that the ETTL seems to behave more like what you'd see on camera so I found that to be a big positive.

Given the insane price of the new flashes it's hard for me to tell you to upgrade to the new system, but I think it might be a nice addition to your wish list.

mabou2 said...

Hi Ron,

I am rushing though the instructions to try to use my two new 600 flashes for a shoot tomorrow. I THINK I just read in the Canon instructions that the sync speed for wireless is 1 stop slower than the normal sync speed of my 5dMKii camera. So for me, the sync speed using this setup is 1/125 of a second, which is too slow for my 200MM lens and shooting people that are being active.

When I set the camera to anything faster than 125th of a second, I get a TV! warning in the LCD on the flash, which presumably tells me that sync is not possible, yet when I shoot I don't see any real issues (like a dark band across the bottom that usually signifies a flash out of sync).

Any knowledge of the sync speed issues with the 5DMKii? said...


I always set my camera to Manual(M) mode when using a flash so perhaps that's the issue you are facing.

I could do 1/2000 sec if I wanted to and never had any troubles as long as high speed sync was enabled.

With that said, freezing motion is a function of the flash not your shutter speed so in theory you could be at 1/30 sec and still freeze a jump if you are hitting the subject with enough light.

High Speed Sync isn't for getting a faster shutter speed to freeze motion, it's for using a faster shutter speed to get the correct ambient exposure on a bright sunny day (typically for fill flash). An alternative solution is to use a ND filter so that you can be below the sync speed and not drain your batteries as fast.

Olgierd said...

So here's little update to my original question. I just got 600ex-rt and made test with 7d and Flex TT. Mounted 600ex on Flex TT and was able to use it in ETTL. Range seems to be better than with 580ex2 (I tested only in my condo so no big distance here, but triggered 600ex from bathroom with closed doors where 580ex refused to work. Will go outside today and make another test.

There is however one issue I still have with 5d3 and both 600ex and 580ex2 (no Pocket Wizards involved here).

While shooting pretty much any scene with my 5D3 and either flash with diffuser or small soft box (head aimed directly at target) my 5d3 heavily underexposes (requires +1.5 to +2 FEC). This is true for evaluative metering selected for flash. Switching to average yields correct exposure.
Tested same setup with my 7d and it is not an issue in evaluative (shooting same scene with same field of view, with same camera settings). Don't have 5d2 anymore but for sure I've never seen it underexposing so much.

Oddly without diffuser or with diffuser bouncing off the ceiling exposure is correct or requires small adjustment only.

Can someone put diffuser on his/her flash and try it with 5d3 to see if is experiencing similar issue?

Perhaps I'm doing something wrong here?


Anonymous said...

Hi Ron, I just bought a 600EX-RT wireless flash. I haven't even test it yet. Will I need a 2 parts (slave and Master) or can I work with one flash wireless only?
Im a little confused. I had a Nissin DI866 and I work perfectly fine with one piece.
Can you please provide me with some information? Im kind of confused.
Monica said...


Yes, you need a radio transmitter (purchased separately) to trigger these flashes (a radio reciever only). Certain cameras have IR transmitters built in for the old system, but no camera has the radio transmitter built in (yet).

See my review of the ST-E3 for the most cost effective trigger here: said...




Anonymous said...

Thank you so much!!!!!