i just saw some of your pictures, congrats for you work and passion, and keep them runnig for better and better results.
and about the iso comparation, the one at 3200 was taken with a 40d, and this one at 12800 with 5DmkII, great cameras, but in low light, at high iso... you just can`t beat a fullframe.
all the best !
ps. i`ll share a quote that i just found these days: "start with 50mm prime, and learn to walk before you zoom"
cheers mate!