I know it can be custom done but I'll never understand why one would choose the Copal seven blade aperture over the nice round Ilex. At any rate, I just bought a 10" Commercial Ektar mounted in a Copal #3-S shutter. The front cell uses an adapter but the rear cell screws straight in. Out of curiosity I tried to move the cells to an Ilex #4 but they don't fit. This is a 1961 model Ektar lens. There are no custom markings on the shutter body, cells or the adapter. QUESTION #!: Did E.K. ever factory-mount their Commercial Ektar lenses in Copal shutters? QUESTION #2: If they didn't is there any way to determine who did the work? I'm trying to determine whether or not I should keep it. It arrived with far more cosmetic damage than was indicated in the auction. It's functionally sound though.... unless there's an issue with cell mismatch or misalignment.