Take only what is necessary for radio wireless remote flash and camera control out of the Canon Speedlite 600EX-RT Flash , and what you have left is the Canon Speedlite Transmitter ST-E3-RT.

This transmitter, combined with 600EX, 600EX II, or 430EX III Speedlites makes setting up lighting (from simple to complex) a snap. It's so easy to setup the various groups (from ETTL to Manual to ratios to on/off) right from the back of the camera that you become inspired to try more creative...

I used the ST-E3-RT with 3 600EX-RT flashes for a wedding reception and loved the ease of the system and the results -- that is, when I could focus.There is no focus assist beam when the radio trigger is on-camera, so as soon as it gets dark, focus performance diminishes significantly.

• +

  Superior build quality

• -

  no focus assist

Expensive, but overall a wonderful product. When coupled with a few Canon speedlites, the only limitation is your imagination. The set up and control are easy and user friendly. It is small and only about 3 oz (much better than have a full sized 600EX or even 430EX on top of your camera).

Easy to use and set-up and a perfect way to get the lighting effects you want.

A must have if you need off camera flash features. Works as advertised. Easy to use. ETTL works great.

THIS MAKES YOUR FLASH PHOTOS SO MUCH BETTER. JUST LIKE PROFESSIONAL LIGHTING EQUIPMENT.

This transmitter, together with the 600EX II speedlite, is a match made in heaven. Easy to setup and use. Love that it is RF. It is a bit pricey, but definitely worth it.

This transmitter is awesome. Love that it is radio.

Easy to set quickly right out of the box.

If you own the newest Canon Speedlite off camera this is the unit to get. RF is much more reliable than IR and doesn't not rely on light of sight like the older versions of the transmitter. Yes it is pricey but worth it in terms of convenience and dependability.