Nikon D90 Lens suggestions please?

I own a Nikon D90 with the 50 mm lens, which is great.looking to buy another lens, and don't really want a zoom lens (i use my dslr mostly for indoors/potraits/sports and use a smaller camera for travel). Looking for another prime lens below $300, which can be used on any future camera body upgrades. Can you please suggest between Nikon 35mm f/1.8G AF-S DX Lens or Nikon 35mm f/2D AF Wide-Angle Nikkor Lens? Will FX lens work fine on DX camera? The 50mm gives great pictures for the price, and looking for something similar.

Yes, an FX lens will work fine on a DX camera. It's the other way around that it doesn't. I would not personally buy the 35 f/2 if I owned a D90 and the 35 f/1.8 DX was also available to me, and I did own a D90, and decided that the chance I may upgrade to a D700 at the time was not a factor in selecting the 35 1.8 over the 2D because of its price. It was like $200. And the 35 2D was more expensive and too wide for my taste for normal work if used on a a D700 at the time. You don't always have to factor a lens purchase while using a DX camera with whether you'll upgrade to FX. This is one of those cases. The 35 1.8 is a much better lens than the 2D, way sharper at 1.8 than the 2D is at 2, so the decision was a no brainer for me. It's a lens everyone should have along with a 50mm.

If you are looking for upgrading to a full frame (FX) camera, don't buy a DX lens.

And FX lenses will work fine on a DX camera. Sometimes they work even better than DX lenses.

Reason being is that lenses are typically sharper in the center than in the outer edge of the glass. When using a FX lens for DX, you are only using the center of the lens, so it could in fact be sharper than the equivalent DX lens.

By the way, when I look for primes, I always try to go 2x in focal length from what I already have. Anything else in my view is not enough of a step up or down.

For instance, having the 50mm lens, I would buy a 100mm lens (2x) if I wanted to go up, or a 25mm lens (1/2x) if I wanted to go wider. Anything less is not a significant change.

For that reason, you should be looking at a 24mm lens rather than 35mm.

I can all but guarantee that if you had a 24mm, 35mm, and 50mm lens in your bag, with all else being equal (lens quality, max aperture, etc), you would grab either the 24mm or 50mm lens, and you would never use the 35mm lens.

I have a D90, and I for travel use, I take a 18-200mm lens. However, this lens is not nearly as sharp as primes or less powerful zooms, but for travel use, I'm willing to exchange quality for the convenience of a single lens.

However, for my "home" setup, I usually take a Tokina 11-16mm f/2.8, a Nikon 50mm f/1.8, and a Nikon 80-200mm f/2.8. The "gaps" between the 50mm and other two lenses are not significant, and I have found that I don't need any other lenses to fill in those gaps.

However, and this is a good example of how you should approach it. If I wanted a lens to fill the gap between the 50mm and 16mm lenses, what would it be?

At first, you might think a 35mm lens would be the best as it is almost exactly between 16mm and 50mm. But that would not be the best choice.

While in a linear fashion, 35mm is 19mm more than 16mm, and 15mm less than 50mm, it would be the best choice, optically it is not. This again has to do with 2x.

If you consider the 28mm lens, there's a 1.7x magnification difference between 16mm and 28mm, and a 1.7x difference between 28mm and 50mm, so optically, a 28mm lens is in the exact center between a 16mm and 50mm lens.

My long winded approach is that like many things in photography, you need to think in powers of 2 when it comes to lenses.

Unfortunately, Nikon's inexpensive AF-D 28mm lens is not as good as the 35mm lens, so that is why I have not seen the need to buy one.