2nd curtain sync with a Canon 5D

aka “Merlin’s Rockstar Flash” aka rear curtain flash aka 2nd curtain flash

  1. Hit Menu
  2. Scroll down to custom functions, hit select
  3. Change custom function #15 from a 0 to a 1 to enable 2nd curtain flash
  4. Hook up a flash (if using a 550/580EX, change setting on your flash to enable 2nd curtain, if using a 420/430EX camera controls it)
  5. Change shooting to Tv mode, slow down the shutter speed to 1/30th a second or slower (it won’t work at faster shutter speeds)
  6. Take photo, flash should fire at the start of your photo and again at the end, producing a cool effect of half blurry with some sharpness captured by the flash.

(I’m writing this down because it took an hour of researching down ratholes to find it and I keep forgetting the entire process)


  • Second Curtain Sync is giving you a flash at the end *and* at the beginning??

  • Oh right, I think it just fires at the end — you’re right.

  • Hmmm…I think Merlin’s Rockstar Flash isn’t actually rear curtain flash. When he showed his camera to me, he was turning on a setting on his camera that said simply “slow sync” flash — most point and shoots don’t give you the granularity of front vs. rear curtain sync — so we can’t be certain if the flash fired at the beginning or the end of the exposure. To me it looks like it was front curtain + long exposure.
    Slow sync = camera uses a long shutter speed with the flash, can be used with front curtain or rear curtain
    Rear curtain = flash is fired only at the end of the exposure, works best with moving objects who leave behind motion trails

  • Here’s something I noticed with the Canon 350d and a 430EX flash: second curtain works fine with the flash on-camera in all shutter speed settings, but if you take your flash off-camera (with PocketWizards or cheap triggers) it will only fire second curtain if you use the bulb setting, meaning you need to manually count seconds to get it right.

  • try hashing-up by under exposing does the trick

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