12-21-2025 02:56 PM
Hey guys, I could really use some technical advice. I’m using the Canon R5 Mark II with flash, and I’m noticing a pre-flash happening in both Manual and TTL modes. Does anyone know how to disable this? I didn’t have this issue with my older Canon body, and I haven’t been able to find clear info about it online..
Solved! Go to Solution.
12-21-2025 04:27 PM
Thank you so much for getting back to me. With the help of someone earlier, I was able to figure out that the issue was related to the electronic shutter release. Once I switched to first-curtain shutter, the flash started firing as it should.
It seems that both the electronic and full mechanical shutter modes were causing the flash to fire twice. For reference, I shoot in manual mode with an RF 24–70mm lens and use Godox flashes, both with and without a trigger. The double flash was happening when I fully pressed the shutter button.
My previous camera was the Canon R5, which didn’t have this behavior. Thanks again to everyone for the help I really appreciate it 🙏
12-21-2025 03:54 PM
I've really got no idea to the answer, but I'm dropping a note here to let you know that I'm sure someone here will. I will ask for more details as that will be helpful to whoever does diagnose the problem:
What flash are you using? What mode? A quick search gave this answer "To disable the pre-flash ... you need to turn off features like red eye reduction and potentially set your flash mode to Manual (M) if using a speedlite, as E-TTL (Automatic) always uses a pre-flash"
12-21-2025 03:59 PM
Thank you for your suggestions. I don't have this option red eye reduction in this model. I am 100% sure it is some setting in camera as I have tried serval different flashes and all fired twice in both modes manual and ttl. I also checked the same settings and flash with my older canon R5 and its working fine.Thank you so much for your suggestions, I really appreciate it. I don’t seem to have a red-eye reduction option on this model. I’m fairly sure it’s a camera setting, since I’ve tried several different flashes and they all fire twice in both Manual and TTL modes. I also checked the same flash and similar settings on my older Canon R5, and everything works fine there. Thanks again for taking the time to help 🙏
12-21-2025 04:02 PM
Full Frame bodies & the EOS R7 DO NOT have a red eye reduction setting this is due to lacking a built in flash. This only applies to APS-C cameras with a built in flash. Manual Flash has no pre-flash because you manually set the flash power.
12-21-2025 04:07 PM
Glad to answer, sorry it wasn't more helpful and more authoritative. I've only got the Someone will probably drop in and know the real answer - hope so. I do know the R5 Mark ii supports a the newer Canon flash hotshoe that syncs better with the electronic shutter. For my R6 Mark ii I have to use manual shutter, not electronic. Have you tried the various shutter modes to confirm the behavior in all shutter modes?
12-21-2025 04:10 PM
I should have said "...I've only got the R6 Mark ii to explore.." and "...I have to use manual shutter with my old Speedlite..."
12-21-2025 04:12 PM - edited 12-21-2025 04:14 PM
Hi @ElaTatiana welcome to the forums. What are your shooting conditions like. Is the ambient lighting too low for AF to work. Or is the camera struggling to acquire focus in low light? What mode are you shooting in on the top mode dial ie M, Av, Tv, P, A+ or Fv Modes. Was your older Canon body a DSLR or EOS 35mm AF SLR by any chance? If so those those cameras use a different method to help the camera AF in low light. What flash are you using by any chance is this a Canon Speedlite or a 3rd Party Flash by any chance. When does this "pre-flash" happen. Does it happen when the shutter button is pressed half way or the back button focus button ("*" or "AF-ON" button is configured for AF Start) is pressed. What lens are you using the full name is necessary also are you using native RF lenses. Or adapted EF lenses if so what mount adapter are you using. Is this the Canon brand adapter or is this a 3rd Party mount adapter.
12-21-2025 04:15 PM
That was very helpful. I just tried and it was the electronic shutter 🤦🏻
12-21-2025 04:16 PM
grrr... I need to slow down "...manual shutter.." should have been "...mechanical or elect. first curtain..." But I still don't get a pre-flash. My old Speedlite just refuses to fire with electronic shutter.
12-21-2025 04:19 PM
@SignifDigits only the EOS R3, EOS R1 & EOS R5 Mark II can fire a speedlite with the camera set to the fully electronic shutter. No other Canon mirrorless body can do this. This is a limitation of the image sensor's read out speed. With mirrorless cameras the speedlite has to pulse as if the speedlite is set to HSS to prevent banding.
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