What lens should I use to take nice portraits and get a creamy/bokeh backdrop?

My next lens purchase will be a 50mm or an 85mm f/1.8, and I think it'll give me this, but if there are other affordable lens out there too… It can go on my list of things to get.

I have a Nikon d5100 and I'm on a budget. I'm still teaching myself and learning from a photographer who is also teaching herself… So I don't know all what's out there… And my fundings are low. I save up babysitting and CD money (I make personalized CD's for a photographer), so I need something affordable.

The thing of bokeh is a kind of myth, though is true that quality lenses are not so hard shaping. Usually the brighter lens of a brand serie is more accurate, say 1, 2 or 1, 4 against 1, 8 or higher. But sometimes one asks oneself if such a difference makes a whole, when going to higher weight and price. About if 50 or 80, I think if you get the last one you will miss something when not close portraying.

Because your camera has a cropped sensor, the 50mm lens would be better for you than the 85.To use the 85, you would have to back Way AWAY from your subject, to the point where you might not even have room indoors.

The larger the aperture is on the lens, (say 1.4 as opposed to 1.8), typically the more expensive the lens, though also the larger aperture lenses usually have better build quality. However, you can do well with a 1.8, especially considering how much money it can save you over a faster lens.

Bokeh is a very misused term on this forum. Bokeh is the quality of out of focus HIGHLIGHTS in a photo, and this is mainly determined by the number of aperture blades in the lens, (again, the more expensive lenses have more blades and thus smoother bokeh). What you are actually referring to is shallow depth of field, which is created with larger apertures. You need to realize though, that the larger aperture you use, such as 1.8 or 2.0 will give VERY shallow focus area. You have to be VERY precise with your focusing. You Can't let the camera automatically choose where to focus. YOU need to be in control of focus, otherwise you will never have a face in focus. With a very large aperture, if a head is turned, you focus on the eye that is closest to you. The other eye can very well be softly out of focus when using a large aperture. You are better off to use a little smaller aperture, such as 5.6 and try to have your subject as far from the background as possible.