1. To remote trigger this flash, the camera built-in flash needs to be pop up - The Nissin flash has a built-in detector which required camere build-in to fire in order to trigger the slave mode. Some photographer may find this annoying as they don't want to use the camera built-in flash for their shot.
2. The remote trigger may not be working under bright sunlight - As stated in the manual.
3. The flash will position it's focal length on 35mm when in slave mode - This means that the GN number will be different compared to the full flash power GN number. (35mm, ISO100, GN=22 meters/72 feets)
Based on the fact, this flash on slave mode is best used for indoor as main light source, with camera built-in flash as fill light.
Camera setting (Nikon D40)
Manual Mode (to fix the exposure) on tripod, 1/2 second shutter, 5.6f, ISO 200, Focal Length 55mm, Auto White Balance. One Nissin flash Di466 set to slave mode 1.
Hedgehog tissue box on tripod, 1 meter away from white wall.
>Slave flash positioned at lower back of the subject at 1/16 power. Slight shadow fall behind subject.
Built-in flash -3.0 comp. Slave flash on full power, points towards ceiling, at camera top.
In conclusion, the Nissin Di466 slave mode really worked well for indoor off camera flash photography. I believe above photos can be improved by configure the flash properly plus some accessories (reflector, light meter, umbrella, etc). Nevertheless, this article has proved what the flash can do and now it leaves to your creativity on how you can do better.