edited July 2015 Posted in » Canon SL1 / 100D Forum
I have an older Speedlite 540ez from the film days. Can I use that on my SL1 if needed? I know it weighs more than the camera does lol!


  • edited July 2015
    As I understand it, those flashes will not operate properly in TTL mode on newer cameras, but can be used manually. If the flash has an "auto" setting with its own photocell exposure control, then it can be used as an auto flash with the camera on manual. In those modes, you set the camera's shutter speed at sync speed, the aperture, depending on ISO, as a dial on the flash dictates, and the flash's own internal meter controls flash duration and exposure.

    Later Canon cameras do not tolerate high trigger voltages, but according to the valuable on line resource listed here: (see here) , yours should be all right.

    You will find on that site some instructions for checking any flash for its trigger voltage, which is a very good idea if you have any doubts. Some older flashes have very high voltages and they will fry your camera's brain.

    I cannot speak for Canons and old Canon flashes, but I have a couple of older "auto" mode flashes from pre-TTL days, whose trigger voltages are safe, and they still do a very good job. Not, perhaps, as sophisticated as TTL, but the photocell automatic functions on may older flashes are surprisingly good.
  • edited July 2015
    Thanks so much for the info. Also got a response from Canon and they also said it "might" work but only in manual mode. Will just bite the bullet and spend the bucks for a new one. Anyone need a fairly new Speedlite (for film)?
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