what portriat lens for a 1d?

First off I love the 85L on a 5dmkii, but will not use it enought to justify 2k. So the question is, do I get the sigma 85 or the canon 50L? Since this is a 1.3, i am worried it will be to long for head and shoulders so I was thinking about the 50L. I was going to go back to full frame when the 5d III came out, but I love the mk iv so much I don't know if I will. What are your thoughts?

i would go for the Sig 85. You're only getting the 1.3 crop, so a FF FOV of 110mm. Then you can use it on the MkIII when she comes out.

I would go with the 85 as well. Unless you expect to be constantly shooting in tight spaces, the effective 110mm still provides a good angle of view for head and shoulders shots.

35L and 50L are fairly close in length - almost interchangeable in a lot of situations, in my opinion. I'd go with an 85 because it would be a more even split between your 35L and 135L. I think it would make for a more well rounded group of primes overall. If you were in tight spaces, you could go to your 35 (or your 24-70) and with a bit more room, the 85.