Do you mean a 16-35, Stapler? I didn’t know Canon ever made a 20-35.
They did, it was replaced by the 17-35, which was then replaced by the 16-35, which is how I could afford it. It’s EF, but pre-USM, if that helps date it.
Unfortunately, mine has a scratched/scuffed internal element, which didn’t show up in the pictures, but probably was visible before they got shrunk to ebay size. The exact center is sharp as my 28mm f/1.8, but everywhere else is more kit lens sharp, which is great considering how bad the scratches look, but crappy in every other way.
*sigh*
Otherwise, it’s absolutely great.