Most of Canon Speedlites flashes have quite nice built-in AF-assist LED lights, which would are useful in low-light situations, even when one doesn't want to use flash in photos.

Is there any way to set the flash (or camera) to fire only AF-assist, and not the flash itself? Only way I know is to prefocus and then turn off the flash, which is not very practical.


Disable the flash in the camera settings. It still uses the AF-assist beam, but it will not fire the flash.

The setting is in different places depending on the camera, for example:

Menu > Custom Functions > 07

EOS 5D mk II:
Menu > Tools 3 > External Speedlite control > Flash function settings > Flash firing

EOS 550D / Rebel T2i / Kiss X4: Menu > Camera 1 > Flash control > Flash firing (it also works for built-in flash)

  • Thanks! Does the Mk II variant also work with non-recent models like 550EX or 580EX? I thought that camera-flash control was limited to 580EX II and 430EX II.
    – che
    Jul 20 '10 at 15:35
  • 1
    @che: Yes, I have a 550EX, and it works. Some of the settings only work with newer flashes, but disabling the flash works with older ones also.
    – Guffa
    Jul 20 '10 at 15:36
  • You can't disable the flash and still have the AF assist lamp on the older 1 series Canons (1DmkI&II, 1Ds mkI&II) which is very annoying...
    – Matt Grum
    Oct 28 '10 at 15:34
  • @Matt Grum: That's an odd limitation... Even my old D60 can do that. :P
    – Guffa
    Oct 28 '10 at 18:49

Generally this can be enabled through a custom function on your camera -- depending on your camera, the setting will be in a different place.

In low light situations, the flash may still strobe to assist in metering and determine how much flash power is required.

  • In camera's custom functions I've only found setting to enable/disable AF-assist beam, not having only the AF-assist :/
    – che
    Jul 20 '10 at 12:26

EOS 5D (mk1) and 580EX II AF-assist & no flash:

  1. EOS 5D: {CF7: 1 (=flash off)} & {CF5: 0 (=send)}
  2. 580EXII: {CF8: 0 (Af-assist light on}

Use an ST-E2. It has a focus assist lamp but no flash head. :)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.