topic Re: Canon Lens Connection Error in EF & RF Lenses

Canon Lens Connection Error

mclaughline — Fri, 08 May 2026 12:59:24 GMT

I am a high school photo teacher. We purchased a canon zoom lens EF 24-70 mm 1:4 L IS USM lens with a grant last year. Unfortunately now we keep getting an error message saying there is a connection error with the lens. I have tried cleaning the connection points but it still does not work. Help?

Re: Canon Lens Connection Error

kvbarkley — Fri, 08 May 2026 13:03:53 GMT

What camera?

Do other lenses work on the same camera?

How far back? If less than a year, it should still be under warranty, send it back.

Re: Canon Lens Connection Error

wq9nsc — Fri, 08 May 2026 14:36:44 GMT

I agree with KV, if still under warranty then go that route.

If you change exposure mode to manual and set the aperture to wide open (f4 for this lens), does the error still occur? The 24-70L f2.8 has this issue due to failure of the internal lens ribbon cable that control the aperture stepper but it will still generally work when the lens is set wide open.

Rodger

Re: Canon Lens Connection Error

ebiggs1 — Fri, 08 May 2026 14:47:41 GMT

" I have tried cleaning the connection points but it still does not work."

As you have found out that rarely to never helps or works. In fact you can do more damage than good if done incorrectly. Never use a pencil eraser or WD40 or any other fluid of that type. If you must try, a qtip with some denatured alcohol. Damp not soaking wet. Even a dry lens cleaning cloth is enough. Never touch the contacts with your fingers.

You can try and turn the camera off, remove the battery, wait a minute, and reinsert it.

"What camera?"

Doesn't really matter.

"Do other lenses work on the same camera?"

Yes, try other lenses, do they work?

"If less than a year, it should still be under warranty, send it back."

Unfortunately this is the only remedy, if the suggestions above don't work and other lenses do work.

Re: Canon Lens Connection Error

mclaughline — Fri, 08 May 2026 15:14:38 GMT

Unfortunately we don't have a warranty. We purchase so many cameras and lenses that it gets over looked. Other lenses do work so I know it is the lens and not the camera.

Re: Canon Lens Connection Error

jrhoffman75 — Fri, 08 May 2026 15:34:13 GMT

@mclaughline wrote:

Unfortunately we don't have a warranty. We purchase so many cameras and lenses that it gets over looked. Other lenses do work so I know it is the lens and not the camera.

Give Canon support a call at 1-800-OK-CANON.

Re: Canon Lens Connection Error

mclaughline — Fri, 08 May 2026 15:55:29 GMT

When I just opened the aperture all the way it would allow me to take a picture using manual focus but as soon as I change it the error comes back.

Re: Canon Lens Connection Error

mclaughline — Fri, 08 May 2026 15:56:04 GMT

I will try that. Thank you.