I have a nice Tamron 70-300 VC lens but would like more reach ?? my budget of $700-$800 only means USED..I am looking at Canon 100-400 L IS Ver 1 or Sigma 150-500 OS,,both can be had at or near my limit,,which one would be the best buy...?I am wanting IS,VC,OS so the 400 5.6 is out,, Thanks for your advice.
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Ron








