I buy lots of things from KEH...Very reputable seller... I also have the D7100. Plus I have the non OS version of that Sigma lens. That said, I prefer an older mid 1980's manual focus macro lens for my macro shooting (I have 7 different AF & MF macro lenses going from 55 to 180mm)... The D7100 will meter with the older manual focus lenses in manual & aperture priority modes. I shoot mainly in manual myself. I post lots in the "True Macro forum" here on UHH... Here is a link to a thread over on that forum with examples of macro shots with the older lens... http://www.uglyhedgehog.com/t-237838-1.html#4008204 . Good macro shooting is more about good technique than gear That Sigma gets high marks from dXo mark, but those sites need to be taken with a grain of salt. Real world shooting is a better indicator of a lenses value... Plus, differences between lens scores may not be discernible to most users when viewing images from different lenses... Check out the "True Macro" forum We use any number of different setups when it comes to gear...