Canon EOS - EOS Flash System

EOS Flash System

The flash system in the EOS cameras has gone through a number of evolutions since its first implementation. The basic EOS flash system was actually developed not for the first EOS camera, but rather for the last high-end FD-mount manual-focus camera, the T90, launched in 1986. This was the first Canon camera with through-the-lens (TTL) flash metering, although other brands had been metering that way for some time. It also introduced the A-TTL (Advanced TTL) system for better flash exposure in program mode, using infrared preflashes to gauge subject distance.

This system was carried over into the early EOS cameras wholesale. A-TTL largely fell out of favor, and was replaced by E-TTL (Evaluative TTL). This used a pre-flash for advanced metering, and used the autofocus system to judge where the main subject was for more accurate exposure. E-TTL II, which was an enhancement in the camera's firmware only, replaced E-TTL from 2004.

Canon Speedlite-brand flashes have evolved alongside the cameras. They are capable of wired and wireless multi-flash setups, the latter using visible or infrared pulses to synchronise. Canon also produces Speedlite accessories, including the OC-E3 Off-Camera Shoe Cord which can be used to hand-hold the flash while allowing the camera to control it through the cord. The Off-Camera Shoe Cord is popular among portrait photographers who need to have more control over lighting than a camera mounted flash can offer.

• Speedlite 550EX

• Speedlite 430EX

• Speedlite 430EX II

• OC-E3 Off-Camera Shoe Cord