Hi Arturo,
Just to be clear - the D5200 is not a full sensor body (unfortunately). I was trying to point you away from APS-C bodies if you were mainly looking to work with your 105mm nikkor lens and look for full sensor bodies - which are unfortunately more expensive, but usually come with more bells and whistles. A full sensor camera simply was not in my budget, the new 105mm micro-nikkor was not really either, but having the opportunity to play around with made me really want it. It sounds like you have set of other lenses, so a full sensor body may not be what you ultimately need or is not in your budget.
When I looked into all this I came away with the understanding that an APS-C body essentially behaves as a lens of roughly 1.5 x the given focal length of the 35mm system lens. So a 105mm micro nikkor would behave more like a ~160 mm lens. The 60mm focal length micro nikkor lens I got instead is more like a 90mm 35 mm equivalent. On a full sensor body it would behave like a regular 60mm focal length lens.
