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07-28-2010, 03:03 PM   #1
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Is there a trick to getting Sigma TCs to AF?

I have a Sigma 1.4 TC and a 100-300/4, a combo that is on Sigma's own compatibility list to work with AF, and yet it doesn't. It has worked briefly a couple of times, but I can't get it to anymore. Are there certain settings or parameters that it requires to work?

07-29-2010, 06:15 AM   #2
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According to Sigma, your combination should work. Does this happen in bright sunlight and are you using dark light cutting filters such as a polarizer ? There may be dust or a residue on the electrical contacts blocking communication between the lens and body. I would contact Sigma for servicing. - Service & Support

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07-29-2010, 08:07 AM   #3
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Not had any problems with mine - definately works in the real world as well as the Sigma manual Make sure all lens/converter/camera contacts are clean. Make sure both camera and lens are on autofocus (I know this sounds like a statement of the obvious but I quite often use manual focus and forget to reset things!)
Its not the fastest or quietest focusing combination, but the results are superb.
08-04-2010, 08:10 AM   #4
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Turns out the TC was just defective. The seller allowed me to return it. I have a brand new one coming today, so hopefully won't have any problems with that one.

Thanks for the input.


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