I need an autofocus lens for a Nikon D5000?
More specifically, I'm going to use it for portraiture in a studio setting. I have received suggestions, but it's hard to tell which one will…
1 Definitely autofocus with my camera (Nikon D5000)
2 Produce good quality, sharp images
Naturally, I don't want to spend over $500, but I would appreciate any and all suggestions.
All AF-S and AF-I lenses will autofocus with your 5000.
When using your 18-55, what focal length do you usually shoot at? If you shoot towards the telephoto end (45-55) get a 50 1.8 AF-S. If you tend to shoot towards the middle (30-40), get a 35 1.8 AF-S.
Every lens has it's ups and downs. Generally any with a zoom range will have distortion at some zoom levels, whereas most prime lenses will not. You can normally get an idea of how sharp the images will be by posted pictures if looking on Amazon, although photography specific sites will normally have more detailed/accurate reviews. Also the $500 limit really narrows down your choices… Lenses are expensive.
B&H has good search filters, so my suggestion is use that to narrow down lenses then read through reviews and look on Amazon for sample pictures taken with it before actually buying one.
Try a Nikon 85mm f/1.8D. Fits in your budget without resorting to third-party lenses.
Most Nikon lenses sold today are of the AF-S variety, which will certainly work with your camera. No problem there.
"Good quality, sharp images" are actually more a matter of good lighting. A decent strobe kit will allow you to use the lowest ISO setting (least noise) at a shutter speed of around 1/125-1/250 of a second, fast enough to avoid motion blur while slow enough to sync with the flash. Tripod is a must, no exceptions.
For portraiture, the camera should be at least five feet away (ten would be better). At that distance, you'll need at least an 85mm lens to fill the frame with a bust/headshot. Lens choice here is mainly about avoiding distortion and having as wide an aperture as possible for shallow depth of field. Longer prime (non-zoom) lenses like the 85mm avoid the barrel distortion that is clearly seen in the 18-55mm kit lens, as well as the perspective distortion caused by shooting too close to the subject.
Simply looking for lenses that have G in their name, like 50mm f/1.8G.
Here's a Nikon Lens Buying Guide - http://www.the-dslr-photographer.com/2011/05/buying-a-nikon-lens-guide/