I have a Graflex Optar 135mm f/4.7, in Graphex shutter. I've used this lens with success on B&W films, but am wondering how it will perform with Velvia 50? I've already shot a partial box of Velvia with it, but have yet to develop those shots. So my question is: am I wasting my Velvia on this lens? I'm planning on buying a more modern lens this summer, but would really like to capture some colour sunrises and such this spring while there are still proper transitions between night and day up here in Alaska.