Upload & Sell: On
It is close as makes no difference in sharpness from 2.8 on Woth the 24L II, 35L, 50L and 85LII but has much stronger vignetting until around f4-5.6. It does not replace the primes for low light at all. You need both and you are fooling yourself if you think you can sell/replace the fast primes with the 24-70II except in good light. I was just reminded of this tonight shooting a rock show at ISO6400 f1.2-1.8 1/125-1/200
The primes are not designed for ultimate stopped down performance look elsewhere for that (TS-E 24 II, ZE 21, ZE 25 etc).