What went wrong with my 70-200mm f2.8 vr1 ??

My.  experience is that Sigma TCs do not play well with lenses from other manufacturers. My Nikon 80-200mm f2.8 afs won't even allow the shutter to fire when mounted to the Sigma TC and my old D80. It would also cause the top LCD to flicker on and off. Although it appears to work with my Nikon 70-300VR I don't use Sigma TC with anything except Sigma lenses.

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Snapshott