Is it sharper?

I am thinking of replacing my Nikkor 18-55 mm kit lens with a Nikkor 18-70 mm AF-S DX f3.5-4.5 G ED-IF. I like the extra 15 mm on the high end, as well as hopefully a higher quality image. I will be shooting primarily landscapes, so I will mainly use f/16-f/22 for good DOF. The reviews are mainly positive, but is it worth the cost of the lens ($380) plus a new CP filter ($75) plus tax and shipping. Your thoughts please.

Can you still get a "new" 18-70mm? You can get them used for half the price you quoted. I'm not sure there would be much of an increase in optical quality, either. The 18-105mm or the 16-85mm, especially, would be a step-up in optical quality. The 16-85mm is quite a bit more expensive, though.

Here is a comparison of the DX "consumer zooms":

http://www.bythom.com/nikon-dx-lens-summary.htm

I would not buy one new. They are plentiful on eBay. Believe it or not I still use the 18-55mm VR lens for my family outing kit. I have the Nikon 17-55mm f2.8 for everything else. Once you start using f2.8 zooms, you quickly get spoiled. The Tamron 17-50mm f2.8 is highly rated and close to your price zone. BTW, I very rarely shoot at f22. It's not very sharp due to diffraction. Sometimes I want a soft look to the shot and will use it then.


Kent in SD

I would second that Tamron 17-50mm suggestion, I own the lens and it is very sharp and much better quality than a cheap kit lens plus it has a constant f2.8 aperture.

"I would second that Tamron 17-50mm suggestion, I own the lens and it is very sharp and much better quality than a cheap kit lens plus it has a constant f2.8 aperture. "

I also recommend the Tamron 17-50. I have used that lens for the last year or so and has been great! Much better then the 18-200mm I had and as good as the the 16-85mm I have for my IR set-up.

I am replacing mine with a Nikon 17-35mm – but really only because I shoot in-frame light sources during long exposures (night work in industrial parks) and want better flare control.

Been there, done that, was disappointed. While the 18-70 DX makes the 18-55 DX look cheap, small, and fragile, the optical quality stopped down really isn't that much better (if better at all). Particularly at the wide end, the 18-55 DX is quite good stopped down. If you're going for that lens due to better build quality, non rotating front element, or more reach, you'll be fine. But don't expect a big optical improvement.

Oh, and in addition to that, I'd really check whether you do need that f/16-f/22. Diffraction will reduce sharpness quite a bit (at least on higher resolution sensors, maybe not as much on the D40 you seem to be using). For most of the shots posted to NPN, I wouldn't have guessed that f/16 or beyond was needed to obtain the depth of field required if you chose your focus point well.

Another very well regarded option in that range is the Sigma 17-70 f2.8-4. Probably not quite as good as the ~17-50 f2.8 options from Tarmon, Tokina and Sigma, but its better than the kit lenses.