Toronto. I mentioned in the previous post that Leitz made a special ring so the fiddly little aperture adjustment on the 5cm Elmar could be seen and moved by a ring that went around the accessory. This avoided the risk of poking a damp finger smack in the middle of the front lens element while trying to make an adjustment in the dark.
Unlike on the camera, on the enlarger one had to open the lens fully to focus and then shut down the aperture a stop or two for the sharpest results. Leitz made two rings for the famous little Elmar – pre-war there was the VALAU, a nickel plated gizmo that converted the aperture setting to a number.
Post war, Leitz offered a more elegant and heavier ring called a VALOO that adjusted the aperture but showed the actual aperture at the side of the lens. Beautiful! The deeper design was often used on the camera mounted lens as a sunshade when taking photos.
Of course those with deeper pockets and less inclined to fiddle could buy a lens made especially for the enlargers of the day.