I also have a Nikon D7100. My go to lens is the 18-140 f/3.5-5.6. Great all around lens. I also have the 35 f/1.8, 50 f/1.4, 12-24 f/4 and a 28-300 f/3.5-5.6. I'd love to upgrade to faster glass, but realistically no need for what I do. Like most, my iPhone does most of the duty for everyday, but I still enjoy using the DSLR when the occasion arises.