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Author Message   Harryrag Tinkerer Username: Harryrag Post Number: 183 Registered: 05-2008 Rating: N/A Votes: 0 Posted on Sunday, February 28, 2010 - 05:11 am:    Hi, it's me again, sooner than I thought. I think I know again why I, like you, thought the aperture did not open to the max. This is because I inspected it with the rear lens group plus its ring nut off. In that state it seems as if the aperture is not fully open, because the blades are still visible, but with the lens completely assembled the opening of the blades is wide enough to just match with the rim of the lens cell. If you look in from the film chamber while the shutter is open on B, the difference between f:2 and f:2.8 is distinctly visible when turning the aperture ring. When opening the aperture to the full, the blades stop right at f:2, more than maximum opening is not possible.