what would some of you suggest as a portrait lens for 4X5? although i'd like hea r the details about focal lengths, i'm also interested in particular makes or sp ecific lenses. i have a Speed Graphic, so barrel lens are not out of the questio n. do you use the same focal length for the body shot as well as the head shot? are portraits shot a wider opennings better? any and all comments on this subjec t are welcome. thank you.