Canon 7DMKII vs Canon 5D MKIV - Image quality

[Photog82]

I think the hardest thing for me to get my mind around is this. I use the Canon 35 1.4 II for many of my portraits as well as the Canon 24-105 L. I realize that with the 35 it's basically a 50; but, if I put that on a FF, will I just need to get closer to my subject than I normally do to get the same effect? I have never used a FF so I just don't know what to expect.

Not sure if it would help, but I am normally 4-5' away in this type of photo.