My dad happened to have the 1.8 from an old camera he had. So I was wondering if it's worth it to buy the 1.4 on ebay when I already have the 1.8. Looks like the aperture blades/ iris are a different type in the two, so I guess that would effect bokeh.
I also got my dad's 1.8 from his old SLR days, but just ordered a 1.4 on ebay. but that was also to get a breech-mount with ssc coating. don't really know if it'll be worth it yet, crazy slow shipping..
The f1.8 is the only nFD lens (non breech) to have the lowly s.c. coating instead of the "super" spectral coating (s.s.c.). though none of the nFD lenses say ssc any more.
It also has 6 blades rather than the 8 of the f1.4 and is obviously slower.
I been using the 50 1.4 as my main lens for about three yrs. I had the 1.8, which wasn't a bad lens, but when compared to the faster sharper 1.4 it doesn't compare. I also have the 55mm 1.2, and still prefer the 50mm 1.4 over that huge chunk of glass. There's something about the 50mm 1.4 bokah that I love.