Just a quick heads-up. This evening I took a few shots using my Jessies 360 flashgun. The flash fired as intended etc etc. However, the pictures were totally underexposed. Obviously a synch problem of some sort. Checked all the camera/TTL settings, but they were as normal. Tried my back-up body (I was in the middle of an event, so couldn’t really spend too much time trying to find out what was wrong). Luckily, I just spotted that the slave on-off switch on the back of the flashgun was not quite fully in the off position. Reseated that and all was ok.

The point of this heads-up is that I would have expected (from past experience) the flashgun to not fire at all if this switch was in the wrong position. Or the display panel to show something, or the camera to register some sort of objection, etc. But on the face of it, everything was working as it should, apart from the little matter of the flash not firing when the shutter was open. I’ve never known a flashgun to ‘fail’ like this, so I thought I should share and possibly help someone who comes across the same problem.