Exchange my 35 Art for a 28-70 2.8L (wedding) or sell for Tamron/Canon 24-70 2.8 MKI ?

Are you sure you didn't have fungus? If it "developed". Considering the 28-70 goes for about half the price of a 24-70, and they are generally sharper (albeit heavier). If you are on a budget, I don't see why you would buy the 24-70

Lichter21c wrote in post #17736200
Are you sure you didn't have fungus? If it "developed". Considering the 28-70 goes for about half the price of a 24-70, and they are generally sharper (albeit heavier). If you are on a budget, I don't see why you would buy the 24-70

As far as I was able to gather from Canon, the issue is that on one of the lens elements inside, the coating starts to oxidate over time, and this exponentionalyl increases.
Unfortunately there are no more spare parts for this, since a lot of lenses have been serviced in the past15 years because of this, and spare parts are now gone.

I sold my 28-70 as "lens parts" and got a 24-70 f/2.8

I must say, both lenses were superb, my copies were about the same sharp, yet the 24-70 has weather sealing.

The reason I would not get the 28-70 is simply because of the above issue.
IF this happens, you can't repair it.

Of course you can get 2 28-70's for the price of a 24-70.