The 50mm now.
First up, my initial thoughts on these two lenses were that they were slightly different siblings, but from the same family for sure.
I lost an hour of light, but this is for fun, not science.
Sharpness.
It looks sharper than the 25 to the eye, much like my 40-150 f2.8 looks sharper than the 300 until you look closer. More micro contrast, more contrast overall maybe, but the un-sharpened files can look over sharp.
Easy to attain sharp focus, thanks in part I am sure to the longer minimum focus distance.
Handling.
Slightly tighter focus ring, but much the same otherwise and identical feel on the camera. I did find focussing easier, especially close up, but while it is longer, it does not get as close, so more DOF. The lack of good close focus is not an issue for its intended use (interview b-cam), but for general use it could be frustrating.
Bokeh.
Interestingly, in close-up comparisons anyway, the inability of the lens to get as close does reduce observable Bokeh compared to the shorter lens.
Still very nice, but that snappier contrast creates a slightly different dynamic. My work method with these two lenses is to put a mild 1/8 Glimmer-glass on the 25 and a stronger looking 1/8 Black Mist on the 50, which seems about right.
Very clean separation.
This clarity is on par with my IRIX 150 macro.
Flare.
Like the 25mm, the 50 can handle some stress.
Again straight into the sun.
Lower contrast maybe, but again, not a fair comparison. Basically no CA and great flare control. No issue having a light in frame with these two.
3D Pop.
About the same at the same magnification.
About the same 3d look as the 25, just twice as far away.
Looks soft, but it is shallower depth of field on the long lens.
Some foreground Bokeh, just because I found it so easy.
Sharp, really sharp.
Super sharp.
I am aware there is a slight colour temp shift in these two, but to be honest it is about the same as the difference between my camera sensors, so a slight shift of angle, a different filter or a micro shift in processing is as much. The look of the two is harmonious, but not identical and that is not down to the difference in focal length alone.