I have two Cannon 50mm lenses, one f/1.8 and one f/1.4. I'm just getting 'restared' in photography, since I put my camera's away in the early 80's. Could someone explaine the differences between the two? Is one better for certain situations than the other. Thanks for any help, and I know, I need to buy a photo book and relearn all of this stuff. Thanks, J.