Mark 1 is very sharp at f/4 and very useably sharp at 2.8. The mkii is very sharp wide open and every aperture. If you don't crop the images or pixel peep, the mk1 would do just fine. Pics look great to my eyes but if you want them to look like the mk2, Just add a bit of contrast and color in post

and most people can not tell. I picked mine up used in perfect condition for $1100 last year so I couldn't get myself to justify upgrading to the mk2 for a lens I don't use that much since I have the 85. If you're going to use it for portraiture, you don't want it razor sharp anyways and the bokeh is great on both lenses.