EF 24-70mm f/4L IS USM - Stabilizer violently shaking on R6 Mark II

[Dyushese]

Hello everyone,

I recently purchased a used Canon EF 24-70mm f/4L IS USM lens that was advertised as being in excellent condition with no previous damage. However, after mounting it on my Canon R6 Mark II (using the official EF-RF adapter), I started experiencing a serious issue.

When the lens is mounted and the camera is active, it feels like one of the internal mechanisms goes into some sort of cycle. The lens begins to vibrate or “kick” repeatedly, and the entire camera starts shaking slightly. As a result, the image in the viewfinder jitters and the photos come out blurred.

It strongly feels like the optical stabilizer mechanism is trying to stabilize but cannot lock into position, almost like it is continuously correcting itself in a loop.

Important details about my setup:

• Camera body: Canon R6 Mark II
• Lens: Canon EF 24-70mm f/4L IS USM
• Mount: Canon EF-RF adapter
• Lens condition: used but visually in excellent condition

I have already tried all the basic troubleshooting steps, that are:

• removing and reinserting the battery
• detaching and remounting the lens
• cleaning the electronic contacts
• switching AF on/off
• switching Image Stabilization on/off
• restarting the camera multiple times

None of these steps changed the behavior.

The issue still occurs and the lens continues to vibrate internally as if the stabilizer is stuck in a correction loop.

Has anyone experienced something similar with this lens model? Could this indicate a failing IS unit or another internal mechanism issue?

Any insight or advice would be greatly appreciated!

[Dyushese]

Forgot to mention that I’m sure it’s not the AF system, as it tracks perfectly even in this condition.

[shadowsports]

Greetings,

Do you have any other EF lenses you can test with?

Also helpful if you can post a YouTube video of the sound and if you can let us see the viewfinder that would be great too 😉.  A vibrating image in the viewfinder is a dead giveaway for faulty IS in the lens.

Please visit the AF menu tab 3 and disable > Preview AF if it's enabled.

https://cam.start.canon/en/C012/manual/html/UG-05_AF-Drive_0070.html

If this option is not enabled and the behavior continues, I would contact the seller.   You may have a faulty lens.  

[stevet1]

Dyushese,

The first thing you need to do is isolate the problem.

Do you have another lens you can put on the camera? If you put on another lens, and you still have the same problem, it's probably not your lens.

If you put on another lens and the problem goes away, it's probably not your camera.

Then you'll have to experiment with and without your adapter.

Steve Thomas

[Dyushese]

Hey!

Yeah, other lenses work fine, and all of them have EF mount

[SignifDigits]

Sorry to hear about your issues.  My first recommendation is that if you bought it from someone can can return it, do so.  Just not worth the headache, worry and/or risk.   If not, be aware that Canon service will continue on that lens only through May 2027.  The RF version is a kit lens so they are really plentiful and not crazy expensive.  I went wild and traded my RF f/4 L version in and got the refurbished RF 24-105 F4-7.1 IS STM for $344.  They are $460 new.  No regrets, but then I'm not shooting weddings for a living either.  Of course if I did that I'd probably opt for the f/2.8.    Very happy with the IQ and the lighter, longer and much less expensive glass is a pleasure to work with.  With IS and IBIS I don't notice the loss in stops, and the bokeh isn't an issue for me in that range.  Plus the close focus/macro ability is a nice add, as well.

I hope you get it sorted - just wanted to give you some other options if you can and choose to return it.

[Dyushese]

Thank you!
Indeed, the image in the viewfinder shakes a lot while all of the above is happening.
I followed your instructions, but it had no effect. I believe the IS unit is getting broken.

[shadowsports]

Greetings,

I agree.  We hope you have recourse.  Don't worry, there's always another lens. 

Just one more. 😅

[stevet1]

Dyushese,

It sounds like you have answered your own question.

If other lenses are working fine with the adapter, then you have a bad lens.

It's up to you to decide if you want to try and have it repaired, or invest in a new lens.

Personaly, I would just pitch it and go with a new, and possibly different lens.

SignifDigit's suggestion of a 24-105 is a good one, I think.

Steve Thomas