...Also, you can get backs for 35mm film? I can understand why someone wants to toy around with the 135W, as the format is wider than normal 35mm, but why would you use the 135N? Why not just bring your 35mm slr? Henrik
Look at it this way:
You want to take portraits? A 135mm back using the existing lens (80mm?) makes a great format/lens combination for portraiture (or just passport photos).