# New Sigma teleconverters not widely compatible (yet?)



## ScottyP (Oct 10, 2014)

Only 3 lenses? And I guess you will definitely want the Sigma dock for updates?

http://sigma-rumors.com/2014/10/compatibility-sigma-tc-1401-2001-teleconverters/


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## Mt Spokane Photography (Oct 10, 2014)

This is very weird. The forum will be full of posts from those who bought one and it won't work for their Canon or Tokina lenses either.

Since everyone will eventually update their firmware in the new lenses for one reason or another, its a mess if Canon TC's won't work with them. 

I wonder if the error keeps the lenses from focusing , stopping down, or locks up your camera like the Tokina TC's do with certain lenses? Maybe just error 99??

I certainly would hold off on one of the new lenses if I had to buy dedicated TC's just for them.


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## Steve (Oct 10, 2014)

From the comments on that article:

"I asked Sigma. Here's what they say:

_The converters will work allowing the features they were designed for but not the features of the new converters. Autofocus would be limited to an f/stop of 5.6 or faster when the converter and lens are together_."

So, the compatibility issue seems to be the ability to focus at f8. It seems insane that this is going to be limited to only the three newest Sigma telephotos and not usable with AF at f8 on any other lens. I can't even imagine why they would do this since it must be devastating to potential sales. 

On the plus side, you can put a 1.4 TC on the 150-600 Sport and get AF on the 7DII! Sounds like a great budget birder.


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## Skatol (Oct 10, 2014)

Steve said:


> From the comments on that article:
> 
> "I asked Sigma. Here's what they say:
> 
> ...


The question addressed is in reference to use of the older TC with new lenses. The new TC's are only compatible with the three new Global Vision lenses listed and only after a FW upgrade.
Guess I'll keep my older TC, it works just fine.


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## Mt Spokane Photography (Oct 10, 2014)

Skatol said:


> Steve said:
> 
> 
> > From the comments on that article:
> ...


 
The big issue is the lenses (Future ones will have the new firmware) that cannot stop down below f/5.6 with a Sigma TC. No info at all about Canon or Tokina TC's, but don't expect them to work without checking first.

When you put a f/1.4 TC on the 150-600, it effectively becomes f/8, but with a TC, stopping the lens down usually improves sharpness. It sounds like you are being roped into buying the new Sigma TC if you want to use one with the lens. You can get autofocus at f/11 with a 7D MK II in liveview, so a 2X TC that works with the 150-600 is usable with autofocus. I have no comment about IQ with a TC.


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## Steve (Oct 10, 2014)

You're right, I misunderstood. My brain refused to believe that Sigma would do something that useless and stupid.


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## Mt Spokane Photography (Oct 10, 2014)

Steve said:


> You're right, I misunderstood. My brain refused to believe that Sigma would do something that useless and stupid.


 
I stopped buying Sigma after my five Sigma lenses plus a 28mm f/2.8 rebranded to a generic name all refused to work with my DSLR's. I had to pay $100 to get my Sigma 105mm macro updated, my 400mm and the other 4 lenses became worthless.

I was just getting to the point where it seemed that they might be reliable enough to consider buying one, now, I'm wondering what other surprises we might see.


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## ScottyP (Oct 11, 2014)

I really didn't give them much thought. I assumed they would be like Sigma's lenses, or like Kenko T/C's and they would work on everything. But these are almost as expensive as Canon teleconverters, and they seem aimed at Sigma lenses. 

Maybe Sigma is shifting into a new gear and considers itself less 3rd party alternative to OEM systems, and more of an OEM company.


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## candc (Oct 11, 2014)

I have the 120-300 sport and find the canon series iii tc's to work the best. I am up for trying the new sigmas to see if they are better yet. The statement from sigma says the new firmware update that is required to make the lens compatible with the new tc's makes it incompatible with the older sigma tc's. I would hope that it's still compatible with the canons. I would like to know that before I updated the lens in case I want to keep using the canon's.


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## candc (Nov 23, 2014)

i bought the new tc-2001 and updated the firmware on my 120-300s. just to clarify.

the lens still works fine with the canon and kenko tc's

the new sigma 2x seems to be a bit sharper than the canon 2xiii and the af is faster with the sigma. the bokeh is better with the canon.

the 120-300 + sigma tc-2001 + kenko pro 1.4x also works suprisingly well and gives good results on the 6d, not so good on the 7dii


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