For portraiture on 5x7 I find the 250 to 300mm length in modern glass works just fine. If I want the vintage look I have a 270/f7.2 Shulz&Billerbeck Euryplan, 280/f11 (11in) Goerz APO Artar, 360/ f5.5 R Knoll Soft Focus lens, a 356/f6 Wollensak Veritar 14" SF lens and a 270/f7.7 J. Laack Normal Polynar, all used with a Packard shutter. You can pick up lenses like these in-barrel fairly cheap. They each give a different look for portraits. Remember that you need additional bellows extension for close focus with longer lenses.