The Metabones SpeedBooster reduces focal length by √2 and increases lens speed by the same. So a 50mm f/1.4 becomes a 35mm f/1.0. Keeping in mind that those numbers are the same thing in format-equivalent terms.
Naturally the unusual strong performance of the Sigma 50mm f/1.4 DG HSM made me wonder what an f/1.0 could look like on the Sony A6000, an idea that seemed worth at least some play. Perhaps even on a curved wine bottle. The result* is really quite incredible. No haze or nasties are seen; the image focusing at 11.7X looks crisp and contrasty (dark edges are the lighting).
This crop sections measures 80mm in width while curving around the bottle, thus presenting quite a challenge to a lens to do more than just blur most of it. As shown, it is actual pixels from the Sony A6000 at f/1.0. Detail and micro contrast are far beyond what I would expect at the format-equivalent f/1.4 aperture from the Leica Noctilux or Summilux. For about 1/8 to 1/15 the cost. The world changes.
* Shot handheld at 1/125. All that extra mass of the Sigma 50/1.4 is a big plus when shooting handheld. One wonders why not just design a lens of the same size for APS-C with essentially the SpeedBooster built-in, rather than trying to make the lens smaller? This goofy idea that image quality should be sacrificed to keep lens size down needs to be extirpated by some vendor.