I have the 1.8. If I were to go with the 1.4 version, how beneficial would that be? Shutter speed, here... I just plugged in my 50mm 1.8, and in the current lighting situations (morning, haven't turned on lights yet) here are my tests. F/5.6: 1/4 F/4.0: 1/8 F/2.8: 1/15 F/1.8: 1/60 So, basically I'm wanting to fill in a couple blanks: F/1.6: ___ F/1.4: ___ Any ideas what I'd be looking at here? I mean, will 1.4 really make a difference?