Go search on ebay. I am sure there are plenty of glass that is between 20-30mm and faster than f/2.
Is this posted at the right place?
M42 was originally a pentax mount if I'm not mistaken.
And yes, I've actually checked out eBay after finding a database of all M42 lenses, however I wanted to see if anyone had any experience with these and could point me the right way.
Im currently watching eBay for 2 auctions, one for a fuji lens, and one for a vivitar. [35mm and 28mm respectively]
I think fujinon lenses should be pretty good, how about vivitar?