Old but good and can work with digital (not in Program Mode)
Old but very good.
Designed for A series film cameras, it can be used on Canon EOS cameras.
Communication between the flash and the camera is very limited.
You must set the ISO on the Flash.
You must set the zoom if you want to alter the beam from wide to narrow.
It will pan and tilt (bounce flash)
You cannot use the Program mode on EOS cameras (film or digital)
In Manual mode it just fires at full or 1/16 power - you set it.
But the good bit is auto - f/no set. You choose an f/no you want to use and set it on the flash and the camera. The flash monitors the light reflected from the subject (direct or bounce mode) and cuts off when enough is received. So perfect flash exposure.