Basically I have a Nikon 17-55mm f/2.8 DX AF-S G lens that I bought some time back. Doing a quick check, I realised the resale value is now below $1K in the forum here. Nikon website put price the around $2.5K. Thought Nikon lenses usually hold value pretty well. If I were to sell it, looks like I'm going to be prepared to lose big time. Any idea why? Or only certain lenses hold value? Thought this is a very good lens.