Hello everyone, i have a Nikon d5100 camera and i bought Tokina 11-16mm few months ago, planning to purchase a used 17-55mm 2.8 lens soon. But i wonder if it is better to get Nikon d610 instead? If i go into fx system then i might get tamron 28-75mm lens or a used 24-120mm f4 lens first, then i need to spend much more. Which combo is better in short/long term? Thanks.