After reading several reviews of the Nikkor AF-S 55-300mm F4.5 zoom lens and comparisons with other Nikon zoom lenses, I got the 55- 300. KEH had one in stock--a Nikon factory-refurbished lens at a VERY good price. I put it on my D5100, and I am very pleased. It's very good for portraits because it lets you take shots from a distance that leaves subjects comfortable. An F2.8 would be better, if you can spend 5 to 10 Times what I paid. Over all, the F4.5 is a good compromise for a photographer who has to watch his pennies.