I have one of those older Linhof-branded Compur shutters with the sloping top cone and the little half-moon (fingernail?) cut-away to display the selected shutter speeds. It goes 1 second to 1/200th but then I can't move it over to the 1/400th speed I see just slightly beyond reach. I see a little sliding button that I think is a release catch for allowing me to twist the speed dial over to 1/400th but when I cock the shutter it fires....

So what is the deal? I never heard of this and am afraid to force it.