Tamron 70-200 f2.8 or nikon d2x?

Okay so i have a Nikon d3100 and i'm a photographer in college i have some money and i was thinking should i get a Tamron 70-200mm f/2.8 or a 2nd hand d2x i shoot portraits and i have a 50mm f/1.8 which is perfect for portraits but the 70-200 would be great too: L help!

It's a nice lens for the price and gets great reviews. If you need a 70-200 f/2.8 go for it. I've never had a problem with Tamron but I shoot Sony and they are a subsidiary of Sony so that could have something to do with it. I would stay away from Sigma though - I had two of their lenses when I shot Canon and had to send them both back because they wouldn't work even though they were the right mount.

The D3100 sensor outperforms the Nikon D2x. I would suggest you spend your money on more lenses
From this comparison, you can see why the Nikon D5100 is such a popular body.

.http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/(appareil1)/698%7C0/(brand)/Nikon/(appareil2)/664%7C0/(brand2)/Nikon/(appareil3)/207%7C0/(brand3)/Nikon

Nikon D2x… That's like taking a kid who's used to driving in a Toyota Prius and gving him the keys to a bugatti Veyron