BMPCC + Nikon DX 18-55 3.5-5.6 = DARK!

I have been using this lens previously on my DSLR and it wasn't too bad for the price I paid, but now I mounted it on my BMPCC using a MFT adapter, and it's just so dark I'm wondering if it's normal? Outside I can get away with it under sunlight, but inside, even with the ISO bumped up all the way to 1600, you can barely see things. I know that lens is not rated too well for indoors use, but like I said it was OK on my DSLR and it's the BMPCC that makes it look so bad. Could it be related to the cheap eBay MFT adapter? FYI i'm on the latest firmware 2.1 and I have uploaded a video screen capture of a products display taken from inside a retail store, for your reference.

You might already have done so but check the shutter angle setting. See what it looks like at 180 degrees

Also make sure the aperture is as wide as it goes at f3.5.
If the adapter doesn't let you control the aperture maybe you could try setting the lens to f3.5 with the dslr camera body.

Could it be related to the cheap eBay MFT adapter?

Yes, if that adapter isn't specified for Nikon G-type lenses (i.e. Nikon lenses without an aperture ring). Nikon G adapters for MFT usually have a stepless aperture control ring near the lens mount. If your adapter doesn't, then it could be that your lens is stuck at F22 without any possibility of opening up the aperture.

It should be said though that f3.5-5.6 isn't very fast for unlit indoor shooting to begin with. Your Nikon camera might go up, in auto mode, to 3200 or 6400 ISO to compensate for the slow lens. You can push ISO with the BMPCC, too, not in-camera however, but only in post.

Thanks for your input.
That pic was taken at 180 degrees shutter angle already, and I changed it to 360 and it's much better now, although far from enough. I did put the lens back on the DSLR and adjusted it to f3.5, then mounted it back on the BMPCC but that didn't work out, it's still too dark. Guess I'll have to try another MFT adapter, but for Nikon G now.

Nikon G lens Iris control is mechanical, so without an Iris control ring engaged on the lens, (camera or adapter) the lens will stop back down to f/22, as it has a spring on the lens' Iris lever to close it down, and the adapter/camera lever opens it back up. The Metabones MFT/Nik G adapter is very well made, and has a nice Cam action on the Iris control ring (it adds the missing Iris ring to the lens).

Also, if you need more light, the Metabones BMPCC/Nik Speed Booster is excellent, adapts the lens, increases the angle of view by x.58 and increases the light to the sensor by 1.8 times, so your f/3.5 lens is more like a f/2.0 wide open.
Cheers