Originally posted by Reptilezz thanks guys, Clockwork, i mainly shoot grey fantails and other small birds around my yard and i know that those two lenses are completely different but i have a very tight budget so i think i might just go the k5ii because i probably won't have the money for a better lens if i got the nikon. i actually just watched video on utube of a k5 with a 70-200 tammy and the auto focus was very fast compared to the crappy super zoom i have now.
for birding, and especially small birds, long lens are better than short, even if the AF isn't fast, most small birds (song bird) are nearly impossible to catch in flight, if you want to catch them in flight, focus trap (which doesn't require fast AF), or one of those really expensive lens, and most of the time focus trap is still going to be more reliable to get a sharp shot.
So in retro spec, I actually recommend the sigma 170-500, they run around 300-400 bucks used, or if you want a slightly better lens, the tamron 200-500 or sigma 150-500 or sigma 50-500.
Nikon D7000 is a good camera, but because of the new sensor in the D3200/5200/7100 I would go ahead and place the D5200 over the D7000, for the sensor and the swing screen.
And for song bird, most of the time I see people lure the bird in to take picture, they don't chase it around. with BIF they do chase it some what, but it's more of using their vantage up a hill or cliff, and wait
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High MP counts, because you'll be cropping, AF doesn't count so much because most of the time you'll be using the center focus point for birding.