The Leica III was a screw-mount, coupled-rangefinder built by Leitz Wetzlar in the early days of WWII: 1933-1939. Leica used different model designations, so the Leica III is known by some as the Leica Model F. It's a bit confusing because the variants of the Leica III are referred to as the IIIa, IIIb, IIIc, etc. using lower-case letters.
The Leica III was followed by the IIIa (1935-1940, 1946-1948), which was in turned followed by the IIIb (1938-1940) and then the IIIc which spanned through the post-War period (1940-41, 1946-). The IIIc is the preferred model by many collectors as it has a solid, die-cast body (rather than separate parts) and a redesigned shutter. The Leica IIIf is one of the most usable since it has flash synchronization, and the IIIg is the best of the III series with its large projected brightframe finder, but it was produced in small numbers, is rare, and very expensive.
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