that lens is a tessar with 238mm coverage (I've read---not from ilex catalogue)....4x5 needs coverage of at least 163mm...so you've got 238-163 = 75mm coverage extra over the diagonal...that's 75mm/2 = 37.5mm or about 1.5 inches of play room at the diagonals..you will get less rise than that since you'll hit the diagonals first....it's adequate in my book