Review on Canon 6825B002 Speedlite 90EX Flash by Jontrell Fernandes

The 90EX was designed for the EOS M kit but will work with any E-TTL capable camera. I bought a 90EX flash to use as a missing pop up for my 6D and I fire E-TTL Speedlite flashes off the shoe. A guide number of 30ft/9m at ISO 100 means the 90EX's performance is similar to that of a pop-up flash. Why is the 90EX good? As a flash, it's great for fill-in flash, snapshots, or macro photography when using the cord from shoes. It's not strong enough for group shots. With Sanyo Eneloop AAA batteries, the full charge time is about 2 seconds. I haven't tried alkaline batteries, but reviewers report that alkaline batteries take twice as long to recycle as rechargeable batteries. A unique feature of the 90EX is the Wireless E-TTL Master function: triggers slave units with automatic or manual modes controlled via the camera's flash menu. In this respect it is better than the dedicated ST-E2 master: a brighter and more reliable trigger, manages 3 groups of slaves instead of just two and is useful as a flash when not acting as a master. The 90EX uses light pulses for triggering, so line of sight to the slaves is required. Rotate the slave body so the sensor faces the 90EX. Reflective surfaces in a room (e.g. white walls) often carry the trigger, even when viewed from the wrong direction. Outdoors, however, they don't work without line of sight. Apart from the switch, there are no external controls. Use the flash menu on 2007 and newer EOS cameras to set options. Everything works on my 6D except FEB and high speed sync. However, high-speed sync is available in master mode (trigger mode). Flash exposure compensation can be set via external camera controls, QCS or the flash menu. What I like most about the 90EX is that it's so small and light that I can always carry it in my pocket. My big Speedlite stays behind when I'm not sure I need it. All in all a great mini flash for snapshots, close fills and as an E-TTL controller.