Testing Yongnuo RF-602, Canon 400D and Canon 430EX. Fired into white diffuser. Stated normal sync of 400D is 1/200. Camera handheld.
1. Camera: Manual setting 1/2000 sec shutter speed; f5.6; Flash directly mounted on camera; Flash: Set to high speed sync, ETTL mode; Distance: Approximately 1.5 metres (5ft) - No discernible sync problems.
2. Camera: Manual setting 1/250 sec shutter speed; f5.6; Flash off camera; Flash: Manual mode; 1/64 power; triggered by RF_602; Distance: Approximately 1.5 metres (5ft) - No discernible sync problems.
3. Camera: Manual setting 1/320 sec shutter speed; f5.6; Flash off camera; Flash: Manual mode; 1/64 power; triggered by RF_602; Distance: Approximately 1.5 metres (5ft) - Obvious sync problem.
4. Camera: Manual setting 1/250 sec shutter speed; f5.6; Flash off camera; Flash: Manual mode; 1/64 power; triggered by RF_602; PLUS Custom function in camera set to "03 Flash sync speed in AV mode = 1:1/200 (fixed); Distance: Approximately 1.5 metres (5ft) - Obvious sync problem.
I was surprised at this setting (#4) creating more of a sync problem even when the camera was not set in AV mode. I was still shooting in manual mode.
There has been some discussion on the net about the capabilities of these triggers and high speed sync. A lot of confusion seems to surround this issue. Many comments I've read come from those (1) who don't know the difference from ETTL triggers, like Radiopoppers and Pocket Wizards, and simple manual triggers, or (2) don't actually have these triggers and therefore can only speculate. I have posted this to help clear up the confusion and enable people to decide whether this trigger meets their needs. As a simple, reliable, low cost flash trigger, it is the best that is currently available. Are there better products like this available? Yes, but at significantly higher costs. Undoubtedly, my most boring photo on flickr! Thanks for viewing anyway.