Used to own the tamron 28-75 paired with a D90. Great combination and I miss it so much because it was so light and portable. The tammy was a bit soft wide open but perfectly sharp by f4 nevertheless it was less evident at low light conditions. I now have the nikon 28-70 beast and the D300s and these are just heavyweights. I really lost portability for extra performance but its the price you have to pay. The beast is a totally different animal. It is built like a tank. The tammy is plastic crap. The beast extends very little and the tammy a lot more so more risk of getting dust in. The beast is very sharp wide open and the tammy a bit soft wide open. The beast is a heavy weight and the tammy a feather weight. Both produce rich colors.