This is a sort of continuation from another thread I made recently as I considered mixing things up to shooting a wedding in April. My kit is tailored towards what I mostly do -- family portraits and engagement sessions. The lenses I use for these sessions (in order of most used to least) are the 85 1.8, 135L, 35 f2 IS, and the 17-40L. The 6D does all the work and my 650D stays in the bag as a backup.
I intend to give the 6D the bulk of the work at the wedding (if not all) and for that reason, I've purchased a used 24-70 f2.8L (original version). My thinking is that 24-70L will be mounted on the 6D for the ceremony and likely the reception with a flash + some off-camera lighting. I'll pull the primes out for formals and possibly mount the 85/135L on the 650D during the ceremony to get some closeups/extreme DOF shots.
Now my question is, should I sell my 35 f2 IS to help cover the financial damage of this recent purchase? The 35mm only comes out during portrait sessions to get those environmental shots (which I imagine the 24-70L will do a fine job with) or group shots. In both cases, I'm typically stopped down to f4 or greater. The one thing holding me back is that I could see the 35 f2 IS being useful during the reception.
I'm sure the 35 f2 IS is sharper than the 24-70L MK1, but how drastic are we talking? Will I really miss it given my uses of the 35mm focal length? Bonus question: how does the Sigma 24-70 2.8 compare?









