After picking up a 90mm LS from ebay I spotted another auction for a 165mm LS that did not get much attention. I had only one minute to either pass or place a bid. I chose to place a bid and I won at a price nobody could resist it I believe. When the lens arrived I was surprised by how nice the shape it was in. I remember seeing one at a similar condition in a photo fair but at a price of $500+. Anyway I got it really cheap and it looks really in a beautiful shape. But when I compared it with the 90mm LS I immediately noticed a difference. For both lenses to fire the leaf shutter, after cocking them, you can just manually press (move) the aperapture linkage lever next to the rear element of the lenses. Both shutters fire accordingly. But I see a significant difference. On the 90 LS when I press the aperature lever slowly I can see the shutter blades closing down completely while the aperature blade are closing down to the designated f stop. By further pressing the lever the shutter fires and the shutter blades remain closed afterwards. I can see the shutter blades closed fully before the shutter is eventually fired. On the 165 LS when I press the lever slowly and while the aperature blades are closing down I do not see the shutter blades closing down at all. In fact before the aperature reaches the designated f stop suddenly the shutter is fired. The shutter blades close down quickly and immediately open then close again (open for the duration of the desigated shutter speed). Then the blades remain closed afterwards. I am wondering why is the difference between the two LS lenses. Does it mean one of them not working correctly? I wonder if the 165 LS is supposed to work like that. I wonder if it will synchronize with the focal plan shutter correctly. I guess I can shoot a roll and see if it works or not. But it will take a few days before getting a result. Can any of you who own a 165 LS tell me if mine is likely to be problematic? I know I got it really cheap but it is because of the auction. The seller said it is in excellent working condition.