Beautiful subject & nice framing, but watch out with this lense! Considering the old Pentax SMCA 1.4 was one of the sharpest 50mm lenses of its day (giving Zeiss & Leica a run for their money) it would be a shame if you found yourself with soft shots all the time because of tight DOF. Try stopping down a bit to get better performance out of the ol' 50mm - it took me awhile to learn that but mostly because I love the gobs of great bokeh this lense produces. At f1.4 (wide open), this lens' DOF is measured in fractions of an inch - but there are plenty of times I LOVE that much soft focus so don't take my advice as a rule. FYI, I find that somewhere between f5.6 & f8 are the stops I use when I'm concerned about keeping things in focus.
Lovely expression capture, the crop is perfect for this along with the softness of the skin. The eyes are the highlight, very expressive with the pure whites and sparkle in them!