Just an unofficial test I did during night time. I will find time to do a more comprehensive testing in the future. Using the Vlog-L profile, and Color graded, no noise reduction in post. The Sigma 18-35mm F1.8 with the Metabone Speedbooster Ultra clearly has some vignetting around the corner.
Shot by Sheldon Pang (bokehcreate.com)
Shot on Panasonic GH5S + Metabone Speedbooster Ultra 0.71x
Lens used: Sigma 18-35mm F1.8
Camera Setting: ISO 3200, 180, F1.3(all shots)
C4K 24P 422/10bit/ALL-I 400Mbps