An online guide to collectable cameras and related stuff
Canon Rangefinder Identification Guide
Canon IV Series
The first model of the IV series was actually refered to as the IIC by the factory. They reused that name on a camera that actually belonged in that series later, although it too was a low production item. Most of this model were sold through the Skinner Co. in the US, and he called them the IVM. It is refered to by collectors as the Canon 1950. Most are engravrd "Serviced and Guaranteed in San Francisco California". They may be distinguished from other IV series cameras by the advance-rewind lever, which is on a little step. It is the only camera with the step on which the "R" is not engraved on the step, but rather on the top plate itself. This camera is extremely rare, with a production of only 50. If you have want, please contact us.
The first of the series to be generally available was the Canon IV. If your camera isn't a 1950, but does have the two piece finder magnification lever, and lacks a film speed reminder in the wind knob, it's a IV. Manufactured from 1951-52, only 1400 of them were built, making it rather scarce.
If your camera has a film speed reminder, and the newer style one piece finder magnification lever, but no X on the slow speed dial, you have either a IVF or IVS. Another little story. When Canon introduced the IVF in Dec of 1951, they did not realize that 4-F in military draft lingo meant unfit for duty. Canons were sold heavily on military bases through the PX stores. This was not a stigma they wanted on their top of the line camera. So at the earliest convience, about April of 1952, they came out with the new model, the IVS.
Actually, there is a significant difference in the construction of the two, it's just not something you'd normally change model designation over. The shutter crate, the frame that holds the parts of the shutter together, was made of stamped sheetmetal parts in the IVF. The IVS shutter crate is cast as one piece. It is stronger, and cost less to manufacture than the older style. And a good excuse for a model name change. How to tell them apart without disassembling the camera? Remove the baseplate. Look inside where you would stick the film cassette in. On the wall toward the center of the camera. If you stick your finger inside there, and on the wall of the shutter crate you feel a slightly raised rectangular area, you've got a IVF. If not, it's a IVS. This change was not noted in other models. Production of the two models together was 6900, about 2000 of which were IVFs. The IVS was discontinued in 1953.
Ok, so your camera does have the X on the slow speed dial, which splits at 25. You've got a IVSB. The X on the slow speed dial indicates that the camera is synched for electronic flash,, as well as flashbulbs. This camera was a hit, and from Dec. 1952 thru March of 1955, they built nearly 35,000 of them.
If your camera's shutter speeds split at 30, then it is the IVSB2, the final camera in this series. They were manufactured from 1954 thru 1956. Tortal production was 16,800.