Canon Model IV S (IV F)

Your camera would appear to be a Model IV S. It has the following distinguishing features:

• No Model Name on Camera
• Top Shutter Speed 1/1000th
• Has Slow Speed Dial
• Slow Speed split at 1/25th
• No lock on Slow Speed Dial
• Has Side Rail
• Corporate Name with “Inc”
• 1 pc View Lever

Dates: IV F  –  December 1951 thru August 1952
            IV S  –  April 1952 thru May 1953          

Produced: IV F  –  2000 (Estimate)
                   IV S  –  4900 (Estimate)

Ser. Nos.:  IV F  –  52610 – 69000
                  IV S  –  640000 thru 850000

The Model IV F came first. It was basically a Model IV but it came with the new rigid Serenar f/1.8 lens, a new Universal Thread Flange, new knobs and a new finder selector lever. The camera continued to change with time as improvements were added.

Eventually there was a major internal structural change from a sheet metal structure to a die cast one which is only discernible on disassembly. It was at this point that the name changed. The same change was introduced into the IIIA without model change. However, apparently, according to Dechert, Canon realized that 4-F was a US Army designation for candidates that were not acceptable to Army standards. They felt that their fine camera should not be associated with this meaning and so they changed the model name.

It is really not possible to figure out the differences between the IV F and IV S models externally. And production ran from one to the other in a smooth progression with parts being mixed which really mixes up the designation.