Now I recognise you after looking at your gallery
That Sigma 30mm 'should' be wide enough for your type of shot, only just though. And the 1.4 max f stop 'should' be plenty for these. In fact, any wider and I'd be concerned about distortion.
You will need to watch the DOF at these distances though if you want to use it wide open (Feel like I'm teaching granny to suck eggs here), but I think that you'll be able to stop the lens down a bit and still keep the recomended 1/Focal Length shutter speed. I've had reasonably sharp images, handheld down at 1/30 sec.
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"I meant," said Ipslore bitterly, "what is there in this world that truly makes living worthwhile?"
Death thought about it.
"Cats," he said eventually. "Cats are nice."