I took my Hasselblad out today for the initial test run. I'm confused what Bay 60 means. I initially thought it was 60mm. I have B&W 67mm filters and they seem to be the same diameter as my 80/2.8 CF lens. But the lens has no threads on the front. How am I to attach a filter without threads? And what is the actually diameter of "Bay 60?" Do I need to get an adapter or something to use my filters? Why doesn't Hasselblad just do like all the other camera manufacturers and keep it simple?