As a newbie to LF and on a tight budget I have pieced together a kit over the last year(Cambo SC). I acquired by default a Schneider Xenar 135mm f4.7 which has seen better days optically. Indications are that the previous owner taught Ice Skating on the front and rear surfaces.

I have run a preliminary batch of shots using this lens, trying to test the clarity of the image especially some backlighting through trees and river shots with lots of glare.

Can anybody offer a method of testing without putting the lens on an optical bench to ascertain whether to ditch the lens and look for a cleaner alternative?