In this video Jimmi-Kai shows how to get a 35mm f/0.9 for $350 on Sony APS-C E-mount cameras. He uses a [shoplink 57362 ebay]Canon FD 50mm f/1.2 lens (here on eBay)[/shoplink] and a Lens Turbo II adapter (here on Amazon or [shoplink 57363 ebay]eBay[/shoplink]):
https://www.youtube.com/watch?v=XcX4D9Dq2pI