Not having seen more than a couple of l.f. lenses I'm not sure if this is anythi ng unusual but I've just acquired a horseman 75mm lens in a seiko shutter and th e aperature blades open up quite a bit past the f5.6 marking on the barrell. Lo oking at the markings on the aperature I can open up to 5.6 and the blades insid e are not fully open. The lever to change the aperature can then be turned a bi t more to open it up all the way. Does this sound like the aperature markings a re off and i should consider 5.6 to be fully open and perhaps the true 5.6 marki ng to be more like f/8? Or is this completely normal? My other lens opens up j ust a tad past the 5.6 marking on the barrel but this one opens up considerably so i am a bit suspicious.