I'm getting back up to speed after a long hiatus with 4x5. Looking forward to it, as I have a portrait project I'm eager to try in LF. I have a Sinar F with 90, 150, and 210 lenses. I'll be shooting head-and-shoulders or tighter head shots, and I'm wondering if my 210 is going to do the job. Since I have nothing longer, I can't really experiment to see how it would look. I'd like to be able to throw the backgrounds well out of focus, but still be able to stop down enough to have workable DOF. I like the perspective of longer lenses; for instance, my favorite portrait lens for 6x4.5 format is the 140, so taking a 150 as "normal" for the 4x5, and the 80 as normal for 6x4.5, this would suggest roughly a 250 or longer lens. I realize that simply applying ratios is not the whole story, however. What does everyone here think? What is your favorite "portrait" lens for 4x5 work like this? Thanks in advance, everyone!