topic Re: EF 24-105mm f/4 L - aperture failure (Error 01) twice in 6 months in EF & RF Lenses

EF 24-105mm f/4 L - aperture failure (Error 01) twice in 6 months

radekn — Sat, 07 Feb 2026 18:02:19 GMT

Hi All,

I use a Canon EF 24-105mm f/4 L with a Canon R6 and a Canon EF-RF adapter. For the second time in six months, the diaphragm has failed (Error 01). Does anyone have an idea why this might be happening so often? Is it possible that shooting HDR photos could cause this, or is it just a coincidence?

Thanks for any suggestions!

Re: EF 24-105mm f/4 L - aperture failure (Error 01) twice in 6 months

deebatman316 — Sat, 07 Feb 2026 18:09:05 GMT

Hi @radekn welcome to the forums. Is this the first gen EF 24-105mm F/4L IS USM lens by any chance? That lens is known for flex cable failures. So can you please provide the full name of the lens in question please. Since Canon released a few lenses with that same focal length in the EF Mount. I have example lenses below to help you identify your lens' complete model name.

Re: EF 24-105mm f/4 L - aperture failure (Error 01) twice in 6 months

radekn — Sat, 07 Feb 2026 18:13:16 GMT

Yes, it’s the first generation. I know it’s a common problem, but I’m surprised it happened again five months after first repairement.

Re: EF 24-105mm f/4 L - aperture failure (Error 01) twice in 6 months

deebatman316 — Sat, 07 Feb 2026 18:22:05 GMT

@radekn Have you looked into the RF equivalent lens for your camera. The flex cable will keep failing even after replacing it and service life is ending soon on most EF lenses. It will come to a point where repair will no longer be an option. You'll be in a never ending cycle of replacing the flex cable which won't be worth it in the long run.

Re: EF 24-105mm f/4 L - aperture failure (Error 01) twice in 6 months

ebiggs1 — Sun, 08 Feb 2026 15:27:33 GMT

The problem with the flex cable on model 1 and the AF issues on model 2 seem limited to a certain serial number range. Some folks never have the problem. Unfortunately you seem to have one in that range. I would guess it will continue to happen with your lens. It really surprises me Canon doesn't have a permanent fix for either condition so it seems anyway.