two questions on lenses for Nikon D5000

[nemesis256]

1. I'm thinking of buying a Nikon 18-109mm. I've read that this lens is not as sharp compared to similar lenses. How true is this? I mean, this is the lens that comes with the D90 kit. So it can't be that bad, right?

2. I want to look at third party lenses just to explore more options. What are the top third party lens companies? I already know about tamron and sigma, and there's a third one that I can't remember right now. And since I have the D5000, I need a lens that has the auto focus motor. What terminology do each of the third-party companies use to show that the lens has an autofocus motor?

[OsmosisStudios]

Originally Posted by nemesis256

1. I'm thinking of buying a Nikon 18-109mm. I've read that this lens is not as sharp compared to similar lenses. How true is this? I mean, this is the lens that comes with the D90 kit. So it can't be that bad, right?

Thr 18-105 is better than the 18-55, and a bit better than the 18-135, but it's still consumer-level. A step up from there would be the 16-85, then the 17-55 or 24-70, both f/2.8. It's not BAD, but it's not professional-level equipment either.

Originally Posted by nemesis256

2. I want to look at third party lenses just to explore more options. What are the top third party lens companies? I already know about tamron and sigma, and there's a third one that I can't remember right now. And since I have the D5000, I need a lens that has the auto focus motor. What terminology do each of the third-party companies use to show that the lens has an autofocus motor?

Sigma, Tokina and Tamron are the top 3 most common. For Sigma you'll wanna look for HSM, and BIM for Tamron. Tokina doesn't seem to have their own term for it, from my research.