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.

[Stephen-Blair]

It gave me a poor connection error once, but once I blew and wiped off the contacts, that message went away. For it to work in the adapted body, it left me confused

[deebatman316 · Accepted solution]

This is strictly a lens issue then. Sigma or a 3rd party will need to repair the lens. 

-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

[Stephen-Blair]

That’s what I thought as well. It’s a shame

[ebiggs1 · Accepted solution]

It needs to go back to Sigma for service.

I don't have every "old" Sigma lens made but the ones I do have, a substantial number, all have worked. I have run across a few older Tamron and Tokina lenses that have problems. Matter of fact I have the EX 70-200mm f2.8 which works fine.

[ebiggs1]

"... no matter which firmware I use. I'm currently on firmware 1.3.6."

Keep in mind it is not Canon's job, or goal, to make FW that enables off brand lenses or gear to work correctly on their camera models. In the first place it would be an impossible feat with all the offerings available out there.