GH3 and IR
AFAIK IR photgraphy with a filter is not very sensitive, maybe you just can not get a focus as there is not enough light (IR also focusses slightly to a different position compared to visible light) and the shutter will thus not fire? Try manual focussing or disable focus priority?
It depends on the camera and how effective it is at blocking IR at the sensor. A lot of EM5 users have reported good success with an unconverted camera and IR filter.
I've just run a quick little test and it seems the GH3 is quite good at blocking IR. At least, with a Hoya R72 filter and fairly bright conditions (partly cloudy) I'm getting an exposure in the ballpark of f/2.8, 1/2 second, ISO 12800. On my GX1 (same lens and filter) I'm getting exposure times closer to 1/15. Ballpark estimate puts the GX1 about three stops more sensitive to IR.
This is hardly scientific, but should explain at least part of what is going on.
Im in the habit of sound af/mf together so I didn't notice any problems with the shutter releasing when I hit the button.
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