I have a m43 Panasonic G3, and wish to buy a hotshoe flash that can use as fill-in flash. 1. The issue here is that the G3 built-in/pop-up flash itself does not even have fill-in mode. Can I assume that G3 'does not support' fill-in function at all? 2. Meaning to say, if I buy a compatible Metz or Olympus flash that has FP mode (i.e. flash photography; fill-in), can it perform a fill-in flash for my G3? 3. Or even if I buy a Panasonic brand flash with FP, will it be certain that there will be fill-in flash when I attached it to G3 that seemingly does not have such fill-in function built-in? Thanks.