EF lens autofocus stopped working with R7 but works with T3i

[captinsane]

I have an R7, maybe 1.5 years old, with the cheaper of the two Canon EF-RF adapters. I have a 300mm f4/L that stopped autofocusing on the R7. I was out birding; everything worked as expected for a while until it didn't. I never removed the lens, but kept the camera off while not using it to conserve battery. I carry the camera on a BlackRapid R strap with the tripod nut connected to the tripod foot on the lens. I bought the lens used around 2014 and while it's mostly worked fine, the manual focus hasn't worked in probably 3-4 years, if not longer.

So far, I've tried

• 300mm on my T3i: works as it should
• EF nifty fifty with the adapter on the R7: works as it should
• RF 18-150 on the R7: works as it should
• Cleaned contacts with microfiber towel on all contacts for the adapter and 300mm (I also frequently use a mk1 1.4x teleconverter and have been testing without that, but cleaned the contacts as well)

Best I can tell, the camera firmware is up-to-date. I uploaded some photos after the lens stopped working using the EOS Utility, and it didn't mention the camera needing a firmware update. Also, I've seen on google people saying to clean the contacts with isopropyl alcohol, but in Canon's documentation that came up in a google search, it only mentioned a microfiber cloth, which is why I haven't tried the ISO yet

[captinsane]

It sounds like maybe it just stopped communicating with the camera. I guess I could find a Canon support email address to ask them

[captinsane]

Is there a way to get the attention of Canon for this post?

[Danny · Accepted solution]

Hi, captinsane!  If you'd like our own support technicians to weigh in on this, we recommend getting in touch with them directly.  You can reach them Monday through Friday at 1-800-OK-CANON (1-800-652-2666).  They can troubleshoot the issue with you and figure out a solution from there, and if that includes sending in your camera for repair, they'll walk you through that process, too.

We look forward to your call!

[captinsane]

Great, I will give them a call. Thanks! I was trying to figure out how to do it online, but I don't have my receipt anymore because I bought the lens 12 years ago

[deebatman316]

Good morning @Danny thanks for stepping in while I was out.

[ebiggs1]

"I bought the lens 12 years ago"

Don't be surprised it Canon no longer repairs that lens. If they do check to see how much a used copy of the lens in good working order is. It mat be cheaper to buy a different lens than to repair yours if possible.

[captinsane]

Thanks for the heads up. I called them and they said they do repair it, but quoted me between $230-700+ after I shipped it to them. I couldn't talk with someone who could narrow it down

[Danny]

Thanks for giving our support team a call!  Until our Factory Service Center technicians can get your lens in their hands, a ballpark repair cost range will be the best we can provide at the moment.  Once our techs have had a chance to look at it, they'll email you a free estimate and you can decide what you want to do from there.

Hope to get your gear working again real soon!

[captinsane]

Thanks. I understand it's hard to give a price without seeing it

[ebiggs1]

"Good morning @Danny thanks for stepping in while I was out."

What an odd post was he expecting you to return?