Thanks to the information available in the forum, Pros and Cons of both are clear to me. But I still have a couple of questions I hope you can help me figure out:I've got both on a FF camera, and I use them for different purposes. The 50/1.4 is great for its short DOF (for portrait work or where I really want to highlight a subject by making use of that DOF). Yes, it is a little soft wide open, but I tend to use it at f2 / f2.2 just to add a little sharpness.
1. wide open on full frame, how much I will notice the difference in terms of DOF considering the relatively short focal lenght of both?
2. how much I will notice the difference in term of sharpness (not necessarily wide open)?
The 40 on the other hand, has better sharpness and better contrast. I tend to use it more for a semi-wide landscape lens. For the price and size, the 40 is great to have in the lens bag