Canon EOS 20D Instruction Manual

Using EOS-Dedicated, External Speedlites

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When using an external Speedlite, retract the built-in flash before 
mounting the external Speedlite.

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If the EX-series Speedlite’s firing mode is set to TTL autoflash with the 
Custom Function, the Speedlite will not fire.

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If autofocus cannot be achieved, the external, EOS-dedicated 
Speedlite’s AF-assist beam (if the Speedlite has an AF-assist beam) will 
be emitted automatically (except in <

3> <5> <7> modes).

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The EOS 20D is a Type-A camera that can use all the features of EX-
series Speedlites.

The EOS 20D can synchronize with compact, non-Canon flash units at 
1/250 sec. or slower shutter speeds. With large studio flash, the sync 
speed is 1/125 sec. or slower. Be sure to test the flash unit beforehand 
to make sure it synchronizes properly with the camera.

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The camera’s PC terminal is provided for flash units having a sync 
cord. The PC terminal is threaded to prevent inadvertent disconnection.

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The camera’s PC terminal has no polarity so you can connect any 
sync cord regardless of its polarity.

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If the camera is used with a flash unit or flash accessory dedicated to 
another camera brand, the camera may not operate properly and 
malfunction may result.

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Also, do not connect to the camera’s PC terminal any flash unit requiring 
250 V or more.

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Do not attach a high-voltage flash unit on the camera’s hot shoe. It might 
not work.

A Speedlite attached to the camera’s hot shoe and a flash unit connected to 
the PC terminal can be used at the same time.