Sigma 120-300 f/2.8 Sports + Canon R7 = Complete Failure (works fine on R6/RP)

[kapalabhati]

Hey folks,


I'm going slightly crazy here and need to know if anyone else has run into this specific issue.


The Problem:My Sigma 120-300mm f/2.8 DG OS HSM Sports (EF mount) is completely dead on my Canon R7. I get "Err 01" and literally nothing works - no AF, no aperture control, no IS, no manual focus assist, can't even take a photo. It's like the camera doesn't recognize the lens at all.


Here's where it gets weird:I did systematic testing with all my gear to isolate the problem:


Bodies I tested:

• Canon R6 (latest firmware)
• Canon R7 (latest firmware 1.7.1)
• Canon RP (IR converted, latest firmware)

Adapters:

• Canon EF-RF with control ring (genuine)
• Meike EF-RF with control ring
• Meike EF-RF with drop-in filter

All my Sigma lenses (EF mount, latest firmware via USB Dock):

• 24mm f/1.4 Art
• 50mm f/1.4 Art
• 12-24mm f/4 Art
• 24-105mm f/4 Art
• 150-600mm Contemporary
• 120-300mm f/2.8 Sport ← the problem child

Test Results:
R6: ALL lenses work perfectly with ALL adapters
RP: ALL lenses work perfectly with ALL adapters
R7: ALL lenses work with ALL adapters... EXCEPT the 120-300 Sport

The issue occurs regardless of which adapter I use on the R7 (tried all three).

What I've already done:

• Updated everything to latest firmware (R7, lens via Sigma USB Dock)
• Cleaned all contacts multiple times
• Contacted Canon → "No support for third-party lenses"
• Contacted Sigma → "No known issues with this combination" (seriously?!)

So here I am:

• The lens works perfectly on R6 and RP
• Every other Sigma lens (including my 150-600 Contemporary) works fine on the R7
• Only this specific combination (R7 + 120-300 Sport) fails completely

Has anyone else experienced this? Is there some voodoo firmware version that works? Am I the only person on the planet with this combo?

I'm genuinely baffled because logically, if it was a general R7/Sigma issue, my other Sigma lenses wouldn't work. If it was the 120-300 being broken, it wouldn't work on the R6.

Any insights would be super appreciated before I resign myself to using the R6 for this lens (which kinda defeats the purpose of having the R7's crop sensor for wildlife).

Cheers!

 

[AlanF]

EOS R7 firmware 1.6 / Sigma 120-300 2.8 Sport / Err01

Hello guys! I upgraded my camera to the latest software (Canon R7 - FW 1.6). Since then it does not recognise my lens (Sigma 120-300 2.8 sport).I used it the day before to shoot a football match. I have tried other lenses since then and it worked (Sigma 18-35 1.8, Sigma 50-100 1.8, Canon 18-55...

community.usa.canon.com

 

[kapalabhati]

Hey everyone,

Final update on my Sigma 120-300 f/2.8 Sports compatibility nightmare with the Canon R7.

Latest from Sigma Japan:

Sigma Japan followed up again and provided some really helpful information:

The Good News:

• Sigma Japan sent me photo and video proof of their 120-300mm f/2.8 Sports (Ver. 2.02) working perfectly on an EOS R7 (Ver. 1.7.1)
• They've already contacted Sigma Germany on my behalf and briefed them about my specific issue
• Sigma Germany has an R7 with firmware 1.7.1 and can fully test my lens when I send it in
• They're confident the service team can restore my lens to working order

What They Suspect:

• Since all my other lenses work fine on the R7, the camera itself is not the problem
• The issue is definitely specific to my individual lens unit
• They mentioned the repair might involve "updating the lens in a different way than using the USB dock" - which suggests some kind of internal calibration/firmware procedure beyond what we can do with the consumer USB dock

Next Steps:

• Sending my lens to Sigma Germany for inspection and repair
• Sigma Japan has already coordinated with them, so they're expecting it and know the full background
• They're confident it can be fixed

What This Means for Others:

If you have this same issue (120-300 Sports + R7 = Err 01):

1. It CAN work - Sigma has proven it with their test unit
2. Your specific lens likely needs service - not a general compatibility problem
3. Contact Sigma with your serial number - they can coordinate repair through your region
4. There's apparently a special calibration process beyond USB dock firmware updates

I'm honestly impressed with Sigma Japan's level of support here - they personally tested it, sent proof, and coordinated with the regional office on my behalf. That's pretty solid customer service.

I'll update once the lens comes back from Germany and (hopefully) works on the R7!

Thanks again to everyone who suggested escalating this - turns out persistence pays off.

 

[becceric]

It's great to see this level of customer service.
Fingers crossed that everything works out.