Eric--Thanks for the reply. Based on what you wrote I rechecked. I found that a set screw at the top of the focus extension rod tightened against the short protruding round shaft was slipping under the load of the final compression of the bellows--the lens stage wasn't raising the last inch or so toward the negative stage. Giving the lens stage a manual assist lift along with using the focusing extension did the trick. I think filing a flat on the little shaft for the set screw is in order to eliminate this slippage. Thanks again. njb