Received my RF 16mm this morning from my local camera store and did some testing.
I wanted to provide a few sample images just for reference in case these help anyone.
For my line of work, which is Real Estate and Interiors (both photo & video), this lens is incredible and will be more go to lens.
For photos, I'm typically shooting between f/5.6-7.1 and as expected, it's incredibly sharp; center to corner. Even at f/2.8, I'm extremely happy.
Attached are 3 screenshots of the same image in my office;
(I had to take screenshots because the Canon Rumors uploader wouldn't allow for the large RAW or JPEG files.)
Two images are in Canon DPP4, with one being RAW and the other JPEG; and the last image being the RAW image in LR.
This way you can see the image with the DPP 16mm lens correction applied and without it in LR.
(Both image completely straight out of camera and no adjustments what so ever)
When testing, I shot both RAW + JPEG L;
SS: 1/4
A: f/2.8
ISO: 320
And similar to the RF 14-35 f/4, the 16mm is actually wider than 16mm and relies on the digital profile correction to get it to 16mm, which is why there is so much distortion without the profile correction, similar to my LR RAW example. This must have been how they could get the costs down on the lens.
I also did a test where in LR, if you apply the profile correction for the EF 15mm 2.8, then adjust the distortion slider to roughly +40 you will "straighten out the image"...that being said, if you do a side by side comparison to the DPP RAW file with the 16mm profile correction applied, you're actually getting an even wider field of view, closer to 12-14mm. Again, this is just a test and a "work around" for LR users until the 16mm profile is released. (Take note of how much more doorframe is in this "corrected" image in LR with the 15mm profile compared to the DPP RAW image)
Overall, I am BEYOND thrilled with the performance of the lens, for my purposes at least!
If there's anything else you'd like me to test, let me know.
Thanks for looking!