so which one is better and why? I just need to get as much flash power as possible for outdoor and indoor photography. Are they a lot different from each other?

I couldn't care less about the 600EX-RT's radio capabilities; I won't be using that feature at all. I'm just wondering if there is a difference in the beam quality, aesthetic, power output, etc. If they are exactly the same in terms of flash power and lighting, then I wouldn't bother paying more for the 600EX-RT.


3 Answers 3


Are they a lot different from each other?

They're pretty similar in terms of raw light output, with the 600EX-RT being slightly more powerful. Canon tends to name its Speedlites according to their guide number: the 600EX-RT has a guide number of 60, while the 580EX II (like its predecessor 580EX) has a guide number of 58. The guide number is the maximum distance (in meters) at which the unit can properly illuminate a scene (at ISO 100).

The 600EX-RT replaces the 580EX II in Canon's product line -- the 580EX II has been discontinued. So if you want to buy a new unit, you're going to buy either a 600EX-RT or a 580EX II that's been sitting in the box on someone's shelf for quite a while.

The big new feature introduced by the 600EX-RT is radio triggering. All previous Speedlite models used an optical protocol to control slave units. That worked pretty well, but obviously requires each unit to be able to see light from the master unit.

I just need to get as much flash power as possible

Then at some point you're going to want to use off camera flash, and probably more than one unit. Being able to position flashes closer to your subject and add multiple flashes are the most effective ways to increase your flash power. And that's why you need to think about triggering slave units, preferably before you decide on a system. I use a 580EX and a couple of 430EX II's with the optical triggering, and it works fine. If I were starting now, though, I'd probably buy a 600EX-RT with the expectation that Canon will probably introduce more units that can be triggered with their radio protocol. Another option is to buy third party radio triggers that work with ETTL, like the Yongnuo 622. That can save you some money, but it's more stuff to carry around.

  • \$\begingroup\$ See inkista's answer — the newer flash isn't actually any different in power; it just offers the possibility of a more focused beam. \$\endgroup\$
    – mattdm
    Commented Jan 13, 2015 at 13:38

So which one is better and why?

In terms of convenience and features, the 600EX-RT is better. It has more features, a built-in radio triggering system, and a much better (less cryptic) UI, since it has a dot-matrix LCD display.

I just need to get as much flash power as possible for outdoor and indoor photography.

If you need as much flash power as possible, you should be looking into the Godox bare bulb Wistro flashes or studio strobes and battery packs, not speedlights and their little AAs. Speedlights are the low-end of the totem pole when it comes to flash power/light output.

With the 580EXII and 600EX-RT, however, this is a dead heat. They're exactly as powerful as each other, despite what the guide numbers say. The 600EX-RT can zoom to 200mm, while the 580EXII can only zoom to 105mm. Zooming pushes the flash tube further back into the head to give a tighter, narrower, more focused output. And Canon measures the guide number at the tightest zoom to get the highest number. Which is why the 600EX-RT has a spec. guide number of 60m (it actually varies from 26 to 60 throughout the zoom range), and the 580EX models have a guide number of 58m, but the power output is "virtually the same", according to Syl Arena.

Are they a lot different from each other? I couldn't care less about the 600EX-RT's radio capabilities; I won't be using that feature at all.

If you remove the new wireless RF protocol, then in capability, they aren't hugely different from each other, only in usability. The feature set is roughly the same, but the UI is quite different. For example, with custom settings on a 580EX/580EXII, most of us either have to change them through the camera menus (assuming we have a Digic 4 or 5 camera that can do this) to remember what they are, or carry a little printed card around that tells us what the settings are, because basically they're listed by number, without names, as are the options. Turning on the optical wireless capability requires remember to push the ZOOM button. That sort of thing. The dot-matrix LCD and soft labels for the buttons on the 600EX-RT erases a lot of that confusion.

Syl Arena has the best information on the difference between the 580EXII and 600EX-RT. See also this Syl Arena video for CPN Europe for a sense of the UI differences.

However, for most of us who have read the Strobist and like doing studio-style lighting with our speedlights, the built-in RF capability (and additional features to Canon's wireless protocol) is the biggest reason to buy the 600EX-RT.


In auto, the 600RT will have a longer reach 20-200mm compared to 24-105mm in the 580EX.

The assistance beam is also longer by 4m. the 600RT also supports Camera Menu Options that are not available on the Flash itself. Has more customisable functions, 7 of which can be set as personal functions. the 600 RT has remote Shutter Release Capability and can group more wireless Flashes and also has more Flash Channels Recycling time is slightly quicker.

I use both flashes and find that I don't need the 600rt indoors as the difference in light is miniscule, however, when outside, I find that due to the 2.4GHz wireless, they are invaluable as I can position many 600Rt flashes where ever I want and not have to worry about the power and line of sight as it is the case with the 580ex. As mentioned previously, they do have an increased beam, but only a few meters. aesthetically, to me it is better laid out and more intuituve, otherwise, not a real difference in look, size and power.


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