Flash Creek

Hi, I know this is old post, but wanted to ask if you get any signs of vignette or image degradation on the corners using a BMPCC speedbooster (0.58x) on a BMCC? I have a BMCC and I had an XL speedbooster (0.64x) but sold it. I'm looking into the BMPCC speedbooster, but I have those concerns. Thanks!