Toronto. In the early years of the minicam, leaf shutters were often used to allow for slow speeds. The early focal plane shutter Leicas had speeds from about 1/500 second down to about 1/20th second when both curtains were open.
To allow slower speeds with the focal plane shutter, the release of the second curtain had to be delayed. Leitz accomplished this by using a gear train that delayed the closing of the second curtain by up to 1 second giving the little camera slow speeds from 1/20th to 1 second while still using the focal plane shutter.
This clever idea allowed interchangeable lenses to be used without recourse to leaf shutters or forgoing timed slow speeds. A Leica model B used a leaf shutter but was limited to the 5cm lens. The camera was an unsuccessful model when it was released (1926 to 1930 using two kinds of leaf shutters). Today, it is a very rare Leica model.
The title of this post is from the song of the same name as sung by Michael Flanders with Donald Swann. The song is featured on their LP record, “At the Drop of Another Hat“. Both “At the Drop of a Hat” and “At the Drop of Another Hat” were theatre revues by Flanders and Swann. A subset of the songs appear on each LP (I have both and much enjoyed them).