Nikkor 14-24 on D3100 body until I can afford a full frame sensor?

Does anybody have any insight on using a the lens on a cropped sensor? I want to invest in something that will last down the road for my shots, but want to know if it will be worth it in the mean time with my cropped sensor.

I think the general consensus is that it's better to invest in great lenses with a less than great body, than getting a great body (e.g. D850) and a mediocre lens. With this in mind, it would more than likely be a good idea to go with the Nikkor 14-24mm or something like it such as the new Sigma Art 12-24mm.

Great lenses will always be great lenses, while bodies will likely become much better in the very near future. So yeah, get the 14-24mm and use it on your DX body. You'll loose the ultra-wide angle of view (14mm = 21mm on an FX body).

14-24mm is wide angle on APS-C. It's a great lens for landscapes and large group shots. Bad for portraits.

Only a good idea if you don't want a truly dynamic wide angle of view on the small sensor eg. At 14mm you'd get a field of view of 100 degrees on a 35mm sensor, but only 80 degrees on the smaller DX sensor. (hold up your hand with thumb out straight, now take two fingers away)

While it is an excellent lens, it will add very little to your existing 18-55mm kit lens. It is a little wider at 14mm, but at the long end (24mm), you already have that covered with the 18-55mm. You might want to start investing in prime lenses. They would be useful as portrait lenses for your D3100 and also for the future full frame. The 85mm and/or 50mm would be good investments.

The snag with this strategy is that when you graduate to a full-frame body you will be limited to wide-screen views. This may or may not be OK for your favourite picture-making, but it certainly would not be good for portraiture, where you want something like 80mm or 100mm. It depends a bit on your budget, but something like the 28-105mm f/3.5-4.5D AF would be a much better choice. It would extend your current range considerably, and would be a useful range to have on a future full-frame.

The Nikon D3100 is a nice little camera and it usually comes with the Nikkor kit zoom lens that is 18-55mm… That includes the 14-24mm (minus a mere 4mm on the short end that you will have difficulty noticing while you will notice the additional 31mm added on the long end of the 18-55mm lens). Personally, I think it would be a waste of time, money and effort since it won't add any noticeable perspective you already have in the kit lens that came with your camera (you did buy the camera with the kit lens… Yes?) Save the money and put it aside for a full frame camera with the 18-55mm lens (preferably the f/2.8 version). Buy only what you need and can use; don't become a "lens collector."