topic Re: EF 24-70 f2.8L USM Failure in EF & RF Lenses

EF 24-70 f2.8L USM Failure

KenKPhoto — Tue, 09 Jun 2026 18:47:08 GMT

I have the EF 24-70 f2.8L lens on my R6 Mk II, via an adapter. I just noticed that there are two problems, perhaps related. First, the lens will only zoom down to 28 mm, not 24. The other is an Error 01 (connectivity) and/or an intermittent buzzing noise from the lens when focusing. I used this same setup just last week with no problems. I cleaned the contacts with no change.

My other EF lenses do work, so I believe it's the lens.

Repair or replace with an RF lens?

Re: EF 24-70 f2.8L USM Failure

deebatman316 — Tue, 09 Jun 2026 19:19:52 GMT

@KenKPhoto That lens has known issues with the flex cable. Specifically the version 1 of that lens. The newer R series cameras use much faster communication than any DSLRs could. This exposes older hardware that is failing. I would test the lens on a different native camera preferably a DSLR.

Re: EF 24-70 f2.8L USM Failure

SignifDigits — Tue, 09 Jun 2026 20:18:28 GMT

Just checking. Are you using a Canon adapter? Not that it should matter but folks have reported issues with third party adapters.

Re: EF 24-70 f2.8L USM Failure

KenKPhoto — Tue, 09 Jun 2026 20:35:15 GMT

Yes, I have the Canon adaptor- note that my other EF lenses do work.

Time for an RF lens…

Re: EF 24-70 f2.8L USM Failure

KenKPhoto — Tue, 09 Jun 2026 20:46:52 GMT

I got the same results with my old 5D Mk IV.

Looks like An RF lens is needed.

Thanks for your help.

Re: EF 24-70 f2.8L USM Failure

SignifDigits — Tue, 09 Jun 2026 23:14:03 GMT

Three excellent RF choices there - fixed f/4 and f/2.8 24-105s and the f/4-7.1 IS STM. I had the f/4 but prefer the f/4-7.1 STM personally as 1) I don't shoot weddings or events where I need the absolute best quality in that range, 2) I don't need the f/2.8 bokeh (I can use my EF 100mm f/2.8 or 180mm f/3.8for that), 3) love the weight and size of the STM lens, and 4) love the close-up focus of the STM.

NOT trying to dissuade you from one of the others, just sharing why I am happy with the STM. The IS and IBIS more than compensate for the lost of light stops for anything I care about. I have the 15-35mm in f/2.8 and 70-200 in f/2.8, and just don't even pull the 24-105mm out of the bag all that often. Of course, if I HAD to pick just ONE of those ranges to, I'd carry the 24-105, and if I have an event with a room full of people to shoot that's the one I will most often carry. Outdoors events I use the 70-200mm.

Best of luck shopping!!

Re: EF 24-70 f2.8L USM Failure

KenKPhoto — Wed, 10 Jun 2026 03:59:27 GMT

Thanks for the advice. I will most likely get the 24-105 f4L, as I rented this lens for a trip I took last year. I was impressed by the lighter weight and PQ.

Re: EF 24-70 f2.8L USM Failure

SignifDigits — Wed, 10 Jun 2026 12:08:37 GMT

It's a great lens, and also very plentiful in the used market. Enjoy!

Re: EF 24-70 f2.8L USM Failure

ebiggs1 — Wed, 10 Jun 2026 16:46:42 GMT

"Thanks for the advice. I will most likely get the 24-105 f4L,..."

I would really think that over. It's not the same going from a fixed f2.8 to a fixed f4. Yes the extra FL is great and it might be the right lens for you just really consider how you use your lenses. I owned both and both at the same time. The 24-105mm f4 got sold off and the 24-70mm f2.8L stayed.

"I cleaned the contacts with no change."

Once again and as you found out that rarely, very rarely, to never helps or works. And if done improperly or carelessly can do irreparable damage to the contacts. I've been into digital cameras ever since there has been digital cameras and I bet I can count the times it worked on the fingers of one hand and the thumb doesn't count.

Re: EF 24-70 f2.8L USM Failure

SignifDigits — Wed, 10 Jun 2026 17:36:16 GMT

@ebiggs1 what, specifically are you worried about for the OP? IQ? Low light? The OP has already rented and used the 24-105 f/4 and from that experience believes that they will be happy with it. They will save the $1,000 price difference and half pound to carry.

And the IQ differences with digital correction these days isn't what it used to be. Sure, if I were shooting weddings I could justify the IQ and bokeh differences, but I'm not sure for most of the world most of the time differences are pretty negligible. With IS and IBIS low light has to be really quite low to matter.

The IQ comparison honestly looks better for the f/4 lens to me than the f/2.8 at https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=1415&Camera=1508&Sample=0&FLI=0&API=0&LensComp=1222&CameraComp=0&FLIComp=0&APIComp=0

I just don't see the downside and you weren't specific, so I'm not sure what they are really supposed to think over.

Of course if someone wants to offer me an RF 24-105 f/2.8 L USM Z I would do my best to find a spot in my bag for it and not complain too much about the extra size and 2+ lbs - best of all worlds there, except size, cost and weight - but gotta love that internal-only zoom.

In the meantime my choice for my RF 24-105 f/4-7.1 IS STM was another 10 ounces lighter and about $700 less (got a great deal on Canon refurbished) than the f/4. No regrets at all yet.

Re: EF 24-70 f2.8L USM Failure

ebiggs1 — Thu, 11 Jun 2026 14:31:43 GMT

I only offer my own experiences here. I, me, personally, would never likely go from a top line lens to a lesser lens without, "I would really think that over." So, that is my recommendation. And that's it, there is an end to it.