Understanding exposure

[qunamax]

Hi everyone, new here, I have a couple of questions, trying to understand how exposure works on Yi camera when using script.

So I made a script (with an third party app Yi pro) where I locked ISO@100 and turned on RAW. From what I understand, Yi has a fixed f2.8 aperture, so nothing to do about it, but I'm wondering about the shutterspeed, is it supposed to be AUTO since I didn't specify shutterspeed in the script? That was my intention anyway, lock ISO@100, use tripod and leave shutterspeed to camera, as slow as it thinks it needs for a given scene, but photos seem a bit on the underexposed side, Yi seems a little shy to slower shutterspeeds this way. Anyone have any experience with this? Could it be the metering settings?

 

[Mtz]

Maybe @Nigel can give some advice here.

enjoy,
Mtz

 

[qunamax]

Maybe @Nigel can give some advice here.

enjoy,
Mtz

Thanks for the help, I'll wait for Nigel then.
Just to add, resulting shutterspeed according to exif were always either 1/2s or 1/5s, exif also reads iso100, bit it's on the noisy side tbh, not sure cause I don't know what to expect from this sensor. Anyway photos are underexposed for some reason, I need to dial in about two stops exposure in Lightroom.

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