A quick field comparison of my 3 nifty fifties.

Canon 50mm f/1.8 mkII
Pentax SMC 50mm f/1.4
Pentax Super Takumar f/1.4

Camera is a Canon 60D
ISO:100
WB:4500
Sutter: 1/50th
Used a FaderND

The most interesting thing I found with the short test is how different the lenses handle highlights. The Canon renders more contrast but loses the highlights faster. The pentax's are a bit creamer (although the SMC can be razor sharp, specially stopped down a bit) hold better highlights.

The Super Takumar has the beautiful creamy/dreamy warm color cast from the radioactive element. I'd consider it an effects lens perhaps.

The Pentax bokeh is a lot creamier and very pleasant and not as distracting as the Canon one.

BTW all lenses can be found for under $100
This was also my first try of FCP X... interesting...