The Flash Unit J-2 mounted on a Canon FX and plugged into the PC Socket on the Left Front Panel and shown with the original box and User Manual.

Canon Flash Unit J-2

The later model Canon rangefinder cameras and the Canonflex cameras all synchronized with a Flash Unit through the Flash Unit Connector Socket which was basically a PC Socket surrounded by a bayonet locking ring. Canon abandoned this style socket in the early 1960’s in favour of the PC Socket.

In 1961 Canon introduced the original  Canonet which

appeared with a PC socket for flash sync. Catalogues of the day list the Flash Unit J-2 as an accessory for that first Canonet.

Then in 1964 Canon began the F series of SLR’s with the introduction of the Canon FX which also appeared with a PC Socket for flash sync. And once again, the J-2 was listed as an accessory. In fact, it will work with most cameras that have a PC Socket.

The J-2 is a compact unit with a folding reflector. Inside is space for a 22.5 volt photo flash battery and a removable capacitor. I am assuming this is an electrolytic capacitor. In the 60’s these were not the reliable devices we have today and I presume they had a short life and were therefor replacable. Otherwise they would be hard wired into the circuitry.

The battery charges the capacitor and then when the camera fires the battery voltage is able to deliver a much higher current thus ensuring a positive and vigorous ignition in the flash bulb.

The battery compartment is accessed by moving the collapsed reflector to the side and lifting the cover. The catch is at the bottom (left in the picture). Inside are the Capacitor, seen above in the middle, and the battery. It is a 22.5 volt flash battery such as the Toshiba !15F shown above. Use of the Flash Unit J-2 is explained in the User Instructions shown at the right. Click on the image to open the Instructions.

Canon catalogues of the time list the capacitors in various sizes as accessories available for the J-2. These items would be hard to find now and it is unlikely that they will have survived in operating condition. 

You will see that the manual gives instructions for use with the Canonet camera. Remember that the Canonet had a leaf shutter and so the principles of synchronization are a little different. For the Canonet the Instructions say you can use either F or M bulbs. However, using this Unit on a camera with a focal plane shutter would probably call for an FP class flash bulb unless you were using a slow shutter speed. That would usually be around 1/60th of a second or slower.

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