5D mark iii with Sigma EX 70-200 f2.8 dg macro

[Stephen-Blair]

Hey y'all,

I recently purchased the 70-200mm lens and am trying to use it on my canon 5d mark iii. The lens won't autofocus no matter what settings change or no matter which firmware I use. I'm currently on firmware 1.3.6. I have also ensured that the lens is set to auto not manual. Is there anything that I am missing to be able to use this lens? the autofocus works on my M50 with an adapter, but not on my 5D.

[kvbarkley]

Do you have another lens to try?

[Stephen-Blair]

Yes. I also tried my canon 50mm 1.8, sigma EX 85 1.4, and canon 70-300. They all operated flawlessly

[kvbarkley]

Have you looked to see if sigma has a firmware update that might correct this sort of thing?

[Stephen-Blair]

Unfortunately, this is one of their older lines that doesn’t offer firmware updates through their lens hub

[Waddizzle]

The “EX” in the model number sounds like you have an older version of the lens.  One that is not compatible with the Sigma dock.  

The lens probably has a focus limiter switch, which limits the range of distances that it can focus.  This allows for faster and more accurate focusing at a given range of distances to your subject.

[Stephen-Blair]

The only switch on the lens is to switch from auto focus to manual focus. It won’t focus at any distance. My camera recognizes that it is a 70–200 lens but won’t run the AF

[deebatman316]

Older Sigma lenses may not AF or work at all on new bodies. I experienced this with a Sigma 17-50mm F/2.8 EX DC OS HSM APS-C lens. It worked fine on my old 40D but would not AF on the 90D. I could control the aperture and the IS worked but not AF. I decided it was time to upgrade to FF instead of buying the Canon EF-S 17-55mm F/2.8 IS USM lens. Incompatibilities may arise with 3rd party gear on new bodies.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm, EF 50 F/1.8 STM

430EX III-RT, 600EX II-RT

[Waddizzle]

Not sure exactly which lens the OP may have, APO or not.  But, the 70-200mm f/2.8 EX DG OS HSM was released around 2010 and the 5D3 was released around 2013.  If there were some sort of compatibility issue between Sigma’s top 70-200mm and the 5D3, then I would assume that it should have been addressed years ago.

I would think that some issue with how the lens is fitting onto the camera mount is more likely than a firmware issue.  A firmware issue with the 5D3 would be MAJOR.

Is Canon 5D Mark III Compatible with Sigma APO 70-200mm f/2.8 DG OS HSM 

[deebatman316]

Sometimes dirty electrical contacts can cause this but not always.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm, EF 50 F/1.8 STM

430EX III-RT, 600EX II-RT