Bests & Worsts Reviews from Amazon

For what it's worth, this transmitter does control off-camera Canon brand speedlites... And that's all it does. Which is a bad thing. It no longer has the autofocus assist beam for focusing in low light conditions -- and low light conditions are possibly a principal reason you're using this equipment. It no longer has the optical transmitter function -- and some of your speedlites may be legacy devices. The interoperability of this device is lacking with other Canon and non-Canon flashes currently on the market; and these flashes will continue to be on the market for a long time. Frankly, it makes a lot more sense to purchase a 600EX-RT and use it as a master transmitter with the flash set to not discharge on exposure (yes, you can use the 600EX-RT as a low-light autofocus assist or transmitter without flashing. It's an in-camera external speedlite menu item at the bottom of the menu options.) The 600EX-RT gives you the same master transmitter controls as the ST-E3-RT, but in addition you get the autofocus assist beam, a backwards compatible optical transmitter capability, and a flash bulb. For just a little bit more in price. I've also heard a few people in the industry comment about the placement of the screen facing upward rather than to the rear. I can see how this would be an inconvenience while shooting becaues it requires you to drop your camera off the tripod or monopod to chest or waist height to look at the screen or make adjustments with your free hand. It's a relevant design choice to be aware of. But it's an ergonomic consideration and not one of the design oversights that I'm addressing here. I'm just bringing it up because more than one person has mentioned that it was awkward to make group flash adjustments when they had it held at their waist level. If you are shooting from a lower position, you'll never notice this. There are many people who seem to take the Kanye West approach to reviewing this radio trigger: "Hey 3rd party accessory vendors, I'm gonna let you finish... But Canon makes one of the greatest radio flash triggers of all time... One of the greatest radio flash triggers of all time." That ignores the omissions of important features many of us need in varying applications for our work. What about Pocketwizards? This has virtually the exact same functionality as a Pocketwizard, but the Pocketwizards are cheaper. And other items here on Amazon (the NPT-04 transmitter and receiver radio package is insanely cheap for someone who wants basic radio triggers) like the "4 Channels Wireless/ Radio Flash Trigger Set With 2 Receivers" are much better for amateurs. Yongnuo even reverse engineered this by creating their own model, the "YN-E3-RT". BUT - they added the AF Assist beam that everyone wants and GR mode works for pre-2012 camera bodies! Really Canon? This is a no-brainer. Skip the ST-E3-RT and wait for Canon to release the ST-E3-RT Mark II update that also includes the autofocus assist beam and the legacy optical transmitter functionality. If you want to use only Canon gear for wireless flash, you can use a 600EX-RT as a master transmitter; and even have the option to drop the power down to 1/128 with a light color gel and add a subtle stylistic drama. Canon could have definitely made these better. So Canon. I summarize my suggestions to you for the Version 2 with three points: 1. Add an AF Assist beam to this product. 2. Add a swivel head screen to this product for horizontal and vertical viewing. 3. Add an optical transmitter functionality so we can use our older gear with this.