Currently I use a Nikon D810 camera, which I absolutely love!
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Most of my concert shots are taken using a Sigma 24-70mm f/2.8 IF EX DG HSM AF Standard Zoom Lens for Nikon Digital SLR Cameras. I am eagerly awaiting the new Sigma Art 24-70mm F2.8 DG OS HSM to be released as I intend on replacing my current Sigma lens with this new Sigma Art lens so that I will have the Optical Stabilization that my current lens is lacking.
(Click the image to view/purchase)