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.

 

[Michael Clark]

My experience with using a Sigma 120-300mm f/2.8 | Sports with a 7D Mark II:

I got slightly but noticeably better results cropping images taken using my EF 70-200mm f/2.8 L IS II at 200mm on the same camera body than with the Sigma 120-300/2.8 S at 300mm. My use case was outdoor field sports at night under artificial lighting. The vast majority was high school (American) football over two fall seasons, with a little baseball in the spring thrown in as well.

This was after extensive calibration of the lens and body using the Sigma dock to make a single adjustment at a single focal length and distance, retesting, making adjustment retesting... testing at other subject distances, adjusting, retesting, adjusting, etc.

YMMV

 

[kapalabhati]

Thank you Michael Clark for your experience, the image quality wasn't a part of this discussion.

 

[AlanF]

Thank you Michael Clark for your experience, the image quality wasn't a part of this discussion.

Neither was the weight. I tried to pick one up many years ago and had a shock. As a matter of interest, how do you handle this 3.7kg lens?

 

[kapalabhati]

Neither was the weight. I tried to pick one up many years ago and had a shock. As a matter of interest, how do you handle this 3.7kg lens?

i mostly use it while sitting or with my Berlebach monopod.
The lens weight is not a really big deal for me.

 

[kapalabhati]

Subject: SOLVED: Sigma 120-300 f/2.8 Sports + Canon R7 Issue - Firmware fix worked!


Hey everyone,


Final happy update on my Sigma 120-300 f/2.8 Sports compatibility saga with the Canon R7!


TL;DR: Problem is FIXED!


My lens came back from Sigma Germany today and it's working perfectly now on the R7:

• Autofocus working
• Aperture control working
• Image stabilization working
• No more Err 01!

What Sigma did:

• Inspected the lens
• Applied a new firmware update (not available via USB dock)
• Tested and confirmed compatibility with R7

Everything functions flawlessly now. The whole process took about [insert timeframe] and the service was excellent.

---

IMPORTANT INFO for others with this issue:


After I posted about this, Sigma Japan shared some really valuable information with me. Turns out I wasn't the only one - there's a Korean photographer who contacted Sigma with the exact same problem:

• His 120-300 f/2.8 Sports worked perfectly on EOS R5 and Nikon Z8
• Did NOT work on EOS R7 (same Err 01, no recognition)
• His other Sigma lenses worked fine on the R7
• Both he AND his brother have this lens, and BOTH had the same R7 issue

Here's the key detail: Sigma Japan mentioned that both of these lenses have older serial numbers from before they switched to Toshiba CPUs. This suggests the issue primarily affects older production batches of the 120-300 Sports.


Sigma's technical conclusion:This is NOT a general R7 compatibility problem. It's a specific communication error between certain individual R7 bodies and certain older 120-300 Sports units (particularly pre-Toshiba CPU models). The special firmware calibration they apply during service resolves the communication protocol mismatch.

---

If you have this same issue:

1. Check your serial number - earlier production units seem more affected
2. Contact Sigma supportin your region with:
   • Your lens serial number
   • Camera body (R7)
   • Detailed description of the issue
3. Reference this case - Sigma is now aware this affects multiple users
4. Send it in for service - they have a firmware fix that's NOT available via USB dock
5. Cost: In my case through Sigma Germany, inspection and firmware update was [insert cost info if you want to share]

Bottom line:

• It CAN be fixed
• Sigma has the solution
• Requires service center firmware update (not DIY)
• Seems to primarily affect older production batches

Huge thanks to Sigma Japan (especially Taku Negami) for their outstanding support - they personally tested it, coordinated with regional offices, and made sure this got resolved. That's world-class customer service right there.


Also thanks to everyone here who encouraged me to escalate this and not give up. Persistence definitely paid off!


If anyone else has questions about the process or wants more details, happy to help. Now I can finally use this amazing lens on the R7!