My 50mm f/1.8 has IQ equal to the 70-200II at f/8. So what? How about at f/5.6 or f/4? That's different totally.
You still lose some edges and most importantly, you can't see your composition while you compose. It doesn't work for me but if it works for you, good for you. I won't buy a fish eye anytime soon.
I meant at f/2.8. And I certainly can see my composition while I compose. It's in the viewfinder.
Great work! These four images and the accompanying explanation completely rationalize the statement "no one asked for the 16-35 f/4 IS".
Look at the number of people within this forum itself who have countered your statement. That is a testament to how many did ask for it.
Show me. I saw lots of people looking for a 14-24/2.8. I didn't see anyone looking for a 16-35 or a 10-18.
As someone who has had the misfortune of going through the last 11 pages in a single sitting, I can confirm that there are many people in the previous pages that said that they are looking for a new 16-35. And as someone who has been looking for one myself and thus has been searching through old threads, the CR community in general has been looking for a new one for some time.
I don't care about IS, and I don't care about f/4 vs f/2.8, for my uses. I just want a Canon EF UWA with reasonably sharp corners at f/4. If this proves to be a step up from the 16-35 and 17-40, at this price point, I will be a very happy man.