I don't mind, at least not now. My first 82mm was a Zeiss 21/2.8 ZE, then a Canon TS-E 24/3.5L II. For these lenses, I bit the bullet and bought an 82mm B+W MRC Clear filter (one) and an 82mm KSM CP filter. Now I can use them on my new 24-70/2.8L II. It hurts a bit when you first look at the price of these puppies.
BTW, I'm very happy to say that I found my 82mm KSM yesterday - I hadn't been able to find it since using it this summer in Utah. Big sigh of relief.
The filter size doesn’t depend on the f-number, but rather, the front element size and the need to avoid artificial vignetting.
The new Canon 24-70 mm changed from a negative-lead zoom type to a positive-lead type, resulting in its larger front element. Other positive-lead 24-70 mm f/2.8 zooms like the Tamron and Sigma have 82 mm filter threads for the same reason.
Section 1 of this page talks about positive-lead versus negative-lead zooms, and shows a helpful diagram. It’s for another lens, but the basic idea is the same.
