Up to 4 speedlites can be connected to any EOS camera to provide TTL flash exposure control.

• If the camera has a built-in flash exposure compensation (FEC) feature, this will also work with the multi-flash setup. FEC settings on any attached speedlite will be ignored. AF-assist lights, auto zoom, A-TTL, and 2nd curtain sync are also disabled when using a TTL Hot Shoe Adapter.

• A single speedlite mounted on a Hot Shoe Adapter with no other connections will also have these features disabled.

• If any of the attached speedlites is in manual mode, all speedlites will revert to manual (full power if not otherwise specified).

The EOS multi-flash setup starts with either the TTL Hot Shoe Adapter 2 (HSA2) or TTL Hot Shoe Adapter 3 (HSA3).  The HSA 2 and HSA 3 both function the same with EOS cameras, but the HSA 3 has a hot shoe locking pin on its foot and a locking pin hole on its shoe. A speedlite can be mounted on the Hot Shoe Adapter (which itself is mounted on the camera's hot shoe) and a connecting cord (60 or 300) can be connected to the front. The original TTL Hot Shoe Adapter (no numeric designation) was designed for the T90.  I've personally used one with EOS cameras with good results.

Connecting cords have identical plugs on both ends and interconnect the Hot Shoe Adapter, TTL Distributer, and Off Camera Shoes. The Connecting Cord 60 (CC60) is a coiled cord about 60 centimeters long. The Connecting Cord 300 (CC300) is a straight cord about 300 centimeters long.  The total length of all cords in the setup can be no greater than 1000 centimeters.

Speedlites to be attached off-camera (up to 3) are each mounted on an Off Camera Shoe. Each Off Camera Shoe is connected to a Connecting Cord (60 or 300) which connects to the Hot Shoe Adapter or TTL Distributer.

The TTL Distributer is used when two or three speedlites are used off-camera or to join two connecting cords for greater length. All four jacks on the distributer are of equal polarity; it makes no difference which 2, 3 or 4 jacks are used.

A minimum setup would be a Hot Shoe Adapter, a Connecting Cord 60 (or CC300), an Off Camera Shoe, and a speedlite. The Hot Shoe Adapter would be mounted on the camera's hot shoe, the Connecting Cord would be plugged into both the Hot Shoe Adapter and the Off-Camera Shoe, and the Speedlite would be mounted on the Off-Camera Shoe.

The maximum setup would be a Hot Shoe Adapter, four Connecting Cords (CC60 or CC300, but total length not greater than 1000 cm), three Off Camera Shoes, a TTL Distributer, and four speedlites. The Hot Shoe Adapter would be mounted on the camera's hot shoe and a speedlite would be mounted on the HSA. A Connecting Cord would be plugged into both the Hot Shoe Adapter and the Distributer. Each of the three other Connecting Cords would be plugged into the Distributer and one of the Off-Camera Shoes. The three other speedlites would be mounted on each of the Off-Camera Shoes.

Careful consideration to the placement of speedlites will enable you to control quantity and quality of lighting.  Quantity of lighting can be controlled by:

• manually setting the speedlite "zoom" angle changes the guide number (and strength).  Refer to the Canon EOS Speedlites Comparison Table for guide numbers.
• placement of speedlites at various distances to the subject.  (Speedlite to subject distance determines lighting intensity, not camera to subject distance.)
• use of speedlite models of different strengths.

• relative placement of speedlites of varying strengths (see above).
• placement of speedlites various angles to the subject.
• use of the HSA mounted speedlite for fill-flash.

Viewers since April 16, 1999:

Last updated October 24, 1999