nice pictures ! did you use a polarizer? Which one do you have? I'm interested to buy one but I don't want to risk to loose image quality
B+W has some high quality polarizer filters, i have few and they are great quality, but i moved to square filters so i don't use those round filters anymore, i will keep them for film lenses or maybe just backup if i don't use multi filters.
I keep a B+W KSM Circular Polarizer on my 16-35 at nearly all times. It's not the cheapest CPL out there, but I have never noticed ANY degradation in quality (in, sharpness, flare, or vignetting) - even when I used it on a 5DsR for extremely large-format printing. If I lost or broke mine today, I wouldn't hesitate to buy another (even at full retail) immediately. If I'm not mistaken, the KSM version has better water resistance than their standard CPLs.
Here's a shot from just a few days ago with the KSM CPL. It's uploaded at 4096px on Flicker, so feel free to download the full size image to see what it looks like: