Nikon 18-70mm or 35 f/1.8G?
I have started a small home studio, and own a d5000 for now, also a nikkor AF 50mm f/1.8G a 18-55kit lens, and i'm looking in to getting one more lens for mostly kids and portrait photos. I do like my 50mm it's a really good lens that lets a lot of light in, but it's not an autofocus on my d5000.So i need some help to choose what will be best for my needs? Should i stay with my 50mm or get a 35 AF-S?
The 35mm on your D5000 will be the equivalent of 'normal view' (50mm) due to the crop factor, so I'm not sure that would be best for portraits. Perhaps for group shots or family portraits.
From the reviews I've seen the 35mm is commendably sharp for its price point - but you should investigate the sharpness of any 60mm-90mm lenses that have AF-S. Failing that, then yes, the AF-S 50mm would be okay.
One of the things that you're looking for a lens to do in portrait photography is to have the subject separated from the background. Usually the subject is nice and clear and the background is softly out of focus. To get appealing soft focus, you need a lens that has nice "bokeh". The Tamron 90mm SP is famous for this but I'm not sure how much space you have in your Home studio. Many people are using a 70-300, closer to the 70mm end to get a similar result.
You shouldn't shoot portraits with any lens shorter than the 50mm on a cropped image sensor like the D5000 as they tend to make the subject look fatter. If you're looking for the best image quality, a rule of thumb is to stay with prime lenses; your 50mm is a great example, Nikon's 60mm micro, nikon 85mm or the Tamron 90.
For versatility and if your studio is too small a zoom might be a better way to go. It's easier if your shooting singles or small groups. I'd lose he 18-55 and go to either the Nikon 16-85 or try out Sigma's new version of their 17-70 f2.8-4 macro.
Take a piece of masking tape and set your 18-55 on 35mm. See how that works.
Nikon also makes an af-s version, the 50mm f1.4. If 50mm works well for you that may be your answes.