Canon 600EX RT (18.7 oz./529g with 4-AA eneloop cells, 2.5 second measured recycle time, measured ISO 100 guide number of 29 meters/95 feet at 35mm, rated guide number 36m/118′ at 35mm, 20-200mm zoom head with 14mm wide panel and catchlight card, about $470 new). My biggest source of support is when you use any of these links to approved sources, especially this link directly to it at Adorama (to get the best price you have to add it to your cart) or directly to it at Amazon, when you get anything, regardless of the country in which you live. It helps me keep adding to this free website when you get anything through these links — but I receive nothing for my efforts if you take the chance of buying elsewhere. Thanks for your support! Ken.
Rear, Canon 600EX RT.
The Canon 600EX-RT is Canon’s biggest, fastest, most powerful and most complex flash ever.
The 600EX-RT is the first camera-maker flash with a built-in 2.4 GHz radio trigger system for use by professional wedding photographers. The 600EX-RT system replaces the PocketWizard triggers of the past; all that third-party trigger gear can now be dumped on eBay since Nikon users still need them. Nikon has no radio trigger system, just the older optical trigger system.
Canon also sells a less common 600EX (non-RT) version, which is the same thing without the radio trigger. Both the 600EX and 600EX-RT work with Canon’s existing optical trigger system.
It’s a bit silly to buy just one 600EX-RT, since the magnificent radio trigger system lives for use with multiple flashes. The pro who buys a 600EX-RT doesn’t just buy one or two, he buys at least three or four. You need at least three to light the subject (Key, Fill and Backlight), and another 600EX-RT or the Canon ST-E3-RT transmitter on-camera as the Master to control and trigger it all.
A great thing about this new radio control system is that you can command your entire sea of flashes from the device on your camera. You can run as many as 15 flashes and divide them into 5 groups in the Gr (Group) mode. You get to set each of these 5 groups separately for light level. Shooting amongst other pros? No problem; there are 10,000 different system IDs so no one will pop anyone else’s flashes.
Not only can this new radio system fire flashes, it can also fire cameras. You can shoot 15 remote cameras triggered from your master, for a total of 16 synchronous cameras. I doubt you can shoot all these cameras as well as use those channels for flash at the same time, but I haven’t tried.
The 600EX-RT has obvious status lights on it to let you see if they are linked and OK, or overheated or have low batteries, all from a distance. You can program how some of this works for your own color preference, for instance, the big rear LCD can be set to glow green, orange or red for different states.
The 600EX-RT is for shooters needing small battery-powered radio-triggered flashes. The pro who uses these has assistants running around holding the other flashes on poles for him. For use in a studio, I use real studio strobes instead, which are easier to use, much more powerful and much less expensive, too.
The 600EX-RT is a silly choice just for use on top of your camera. It’s too big and too complex.
Don’t let me stop you, but the Canon 430EX II is a much better idea for on-camera use because it’s more reasonably sized and has a much more legible rear LCD panel. The 430EX II is just as fast and silent, and more than powerful enough for on-camera use (only a half-stop less maximum power), and half the price. The extra power of the 600EX-RT is needed for pros who shoot them bounced off umbrellas, not for on-camera flash. The 430EX II is smaller, faster-handing and less expensive for people who don’t need radio triggers.
Flash exposure is controlled by the camera. Different flashes will give the same results, with the only difference being if they have enough power and if they are ready to shoot fast enough. Don’t think that pictures made with the 600EX will be any better than when shot with the 220EX; so long as you have enough light, which with DSLRs and higher ISOs, you always do.
Loads of effortless power. The 600EX RT keeps belting out the power shot after shot without complaint, even if the flash and batteries may be getting hotter than you think.
Super-fast and silent recycling. You can just keep shooting and the 600EX RT keeps blasting out the power with no waiting.
Built-in bounce card.
Generic dot-matrix LCD crammed with too many things is often difficult to read.
Many buttons have multiple functions as shown on the LCD above them, and that LCD is often difficult to read.
No “A” mode for use with ancient non-TTL cameras. (Its A mode only works when used with 2007 and newer DSLRs).
Great radio trigger system.
Programmable lights and colors so we can see if the flash is OK and connected, or overheated or not linked, all at a glance from a distance.
Flip-down diffuser panel for 14mm lenses on full-frame or 9mm lenses on APS-C.
Manual power mode.
Wireless optical control.
Wireless radio control.
Comes with a little foot to let it sit on a table.
Repeating stroboscopic flash to 500 Hz.
Rain gasket comes down over hot shoe when locked.
It works on all Canon EOS cameras, digital and even Canon’s very first 35mm EOS cameras from 1987.
Canon’s 2.4 GHz system is proprietary; it doesn’t work with PocketWizard or other brands.
For all the radio trigger functions to work with all five groups, you’ll want a camera introduced since 2012, which as of this writing are the 1D X, 5D Mark III, 6D and 70D. Older cameras like the 5D Mark II may only offer three groups.
With all the potential combinations of different cameras and firmware versions, it’s impossible to figure out what exactly works on what until actually you try it in person. If in doubt, buy it from an approved source; never take the chance of buying at retail. Try it all at your leisure at home, and if you’re not happy, return it for a full cash refund. Especially with firmware updates, there is no way to tell for sure until you try it for yourself; you can’t read about it or try it in a retail store — you have to try it yourself with all the rest of your gear.
On 35mm EOS cameras
Everything works great on current 35mm cameras like the EOS 1V.
On the earliest 35mm EOS cameras from the 1980s, TTL and manual exposure and rear sync work great, but the shoe lock, FEL (flash exposure lock) and HSS (high-speed-sync) weren’t invented yet, so these features won’t magically start working.
Even on my 1987 EOS 650, TTL (through-the-lens) exposure, data communication and the green exposure OK light all work great.
With the 1987 EOS 650, the 600EX RT’s computer display cheerfully calculates and displays the flash range as the camera automatically sets the aperture! No problems here with any EOS camera.
On manual-focus 35mm cameras
I didn’t try it on any manual focus cameras like the T90, but it should work in TTL on the T90.
For these cameras, you can get used flashes from 25 years ago better dedicated to these cameras for much less money.
Type A or B cameras and Flash Metering Modes 1, 2 and 3
Canon has never told us precisely and exactly which cameras are A or B or which uses Metering Modes 1, 2, or 3, so don’t worry about it. See more at Canon.
On older (type B 35mm) cameras, you’ll lose some fluff features like FE Lock and High-Speed sync. No worries, everything you need like TTL exposure works great on any EOS camera.
Power (rated, ISO 100)
Recycling Time (rated)
5.5 seconds with alkaline cells.
Batteries and Power (rated)
4-AA cells; alkaline, Ni-MH or lithium.
100 full-power flashes with alkaline cells.
Optional CP-E4 external battery pack holds 8-AA cells, $150.
Goes into Standby after about 90 seconds, wakes with a tap of the shutter button.
20-200mm with 14mm flip-down diffuser.
Smart enough to recognize cropped digital cameras and set itself accordingly.
0º to 90º up.
-180º left to to +90º right horizontal.
The AF illuminator has three emitters: one at the bottom for the center AF sensor, and two above the lower one to light the other AF areas if selected.
Optical pulse or 2.4 GHz radio transmission.
Works as master or slave.
Rated to 50 feet/15 meters indoors or 30 feet/10 meters outdoors, and the slaves have to face the master controller so they can see it.
4 channels (1, 2, 3 and 4).
3 groups (A, B or C).
Lighting ratios up to ±3 stops in half-stop steps.
Batteries will run for 1,500 flashes if you’re using the 600EX-RT as the commander and NOT setting it to flash to expose the image.
Rated to 100 feet/30 meters, but works much better than rated.
2.405 ~ 2.475 GHz OQPSK with DS-SS.
15 channels with manual or auto select, and even has a spectrum analyzer display built in!
10,000 different wireless IDs.
5 groups (A, B, C, D and E).
Batteries ought to run for 9 hours if you’re using the 600EX-RT as the commander only and NOT firing its flash.