Prior to using a Generic Non dedicated flash on the Canon EOS camera, you have to check the trigger voltage of the Flash. The Canon lines of Speedlite flashes do not use more than 6 volts with their trigger circuits. The Canon EOS 1, A2/A2E, 10s, 630, Elan, RT and Rebel operate with 6 volts as the maximum voltage going through their triggering circuits. Therefore you have to make sure that the generic flashes also adhere with this limitation.

Triggering circuits using more than 6 volts can damage the X-Sync contact point of the camera, the connecting wires and shutter units. You might not be aware of the damages as it could be happening gradually. In addition, the high voltage that is conducted through the Camera connecting wire will also generate electro magnetic noises which can create undesirable effects on the Camera functions. Problems can arise from the metering system, shutter speed, aperture settings etc. The effects will depend on which part of the camera circuitry system is being interfered with.

Testing the voltages of the flash triggering circuit is a simple task. Just use a voltmeter which is available at any Radio Shack stores. Connect the positive lead to the positive point of Sync Cord. The Negative lead should be connected to the ground of the Sync cord. With shoe mounted flash, just connect the positive lead to the center point of the mount. The negative lead has to be connected to the grounding point of the camera located at the side of the lock nut. Voltmeters have different setting which you can use. If you are unaware of the voltage of the Flash unit, just use the highest setting on the voltmeter than work your way downwards.

You can actually fire a Studio Flash unit safely without a Sync cord. To do so, just use a Speedlite 420EZ or 430EZ at 1/32 power setting under manual flash mode. Make sure the optical slave trigger is turned on before firing. What you are actually doing is utilizing the bounce features of the Speedlite 420EZ or 430EZ to divert the flash light to the optical slave trigger. On the other hand, you can use slave triggers which are linked by radio signals to fire the Studio flash. These radio transmitters and receivers, which are connected to the Camera’s PC contact and the Flash power packs, are manufactured by companies like Lindahl and Quantum Instruments.

If the EOS camera is not firing the Studio flash, check the following:

(1) That the third party PC socket adapter do not have a metal shoes. This will result in a short circuit in the trigger circuit. The remedy is use Canon PC socket adapter which is made from plastic.

2. Make sure that the flash units polarities are in the correct order with the X-Sync of the camera contact point. The reversed polarities are normally caused by a diode which is coupled to the camera’s X-Sync contact for the protection of the camera internal flash. To correct this problem, simply reverse the polarity of the Sync Cord.

3. If the two troubleshooting tips do not work, just use the method described above on how to fire a studio flash safely.

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Tags: Photography

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