A:Answer It will work an a D3100, which is a "DX" type Nikon camera. On a DX camera, this lens is a short telephoto. That's good for portraits (torso and head shots). It's not particularly good for "long range" shots. That's when you want an 80 to 120mm lens on a DX camera. The kit lens that came with the D3100 probably zooms out to 65 or 70mm. For long range shots, that's better than 50mm.
