I have the Sigma EX 105 f/2.8 and I like it very much....also makes a great portrait lens. I've gotten great results with it... It's a bit heavy, this lens, but as you've discovered 50mm doesn't cut it... Noisy? A bit....but my Nikon's film advance is not quiet either.... not good if you're trying to be sneaky about taking shots... There are others here who also have the same lens and I'm sure they would vouch for it as well.

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