I purchased this camera new in spring 2013 so I have extensive experience with it since then, mostly in the area of astrophotography. In many ways this camera has lived up to it’s promises and I’m overall very satisfied with it.
Why did I choose Nikon in the (at that time) Canon-dominated playing field? Honoustly that might be sentimentel reasons since my father bought a Nikkormat back in the seventies. But I also got a number of lenses from him (he moved on to a digital camera obviously), being a Nikon 50mm F 2, a Nikon 35mm f3 and a Tamron Zoomlens 80mm – 210mm F5.6. That also influenced my decision. And in the end I’m not weary of swimming upstream. Basically it took only a few shots to understand that in fact the 50mm was exceptionally scharp at F/2.8 or F/4. Both other lenses were not suitable for astrophotography. Lens distortion and edge scharpness were just not ok.
Why the D5100?
it was the highest quality Nikon within my budget range. Going higher would almost double the price of the body. I also needed to purchase the 18-105mm Nikon DX zoom so that increased the price. This camera had the same sensor as the higher-end D7000 at that time. The D7000 yielded some nice results so that was an encouragement. The D5100 came with a tilt-LCD screen Since I’m not any of the youngest anymore, all kinds of gymnastics to see the LCD in a – usually – very cold environment ? noooo, not for me. Whenever I replace this camera that will be on my list as well (Jan 2017: did so with the D750). The DX format (smaller sensor then full-format) has all kinds of advantages: you have a denser pixel resolution, which means sharper of higher-resolution pictures that also can be cropped easier. The DX format has a 1,5 crop factor, which means that you can achieve the same image size with a smaller telescope ( a 400mm scope with DX is actually the same image size as a 600mm scope if you would attach a full-frame to it). The DX format also meant that the flat image circle with scharp stars which your optics can produce, doesn’t need to be as wide as with a full-frame.