LPM Graphs of the Minolta AF 50mm lenses.
Not only is the f/1.4 a little faster but it outperforms the f/1.7.
Both lenses are excellent performers, even wide open both are better than any zoom lens.
The sweet spot for the f/1.7 is between f/5.6 and f/11.
The sweet spot for the f/1.4 is between f/5.6 and f/8.
Both are outstanding from f/4 to f/11.
It is unclear what distance this test was run at but probably 3-5 meters.