You are right about the lenses. Many people want the convenience of a "super zoom", so they don't need a lot of lenses. But the larger the gap between lowest and highest focal distance capability, the less overall sharpness of the images. This is on reasonwhy zoom lenses like the 14-24mm f/2.8 and 24-70mm f/2.8 produce sharper images than the 18-140mm mentioned.

Another point to mention is that the smaller the f/stop (larger aperture), the more light-gathering ability of the lens. More light-gathering means lower ISO, which also helps to produce a better image quality.

Just joined, heard this was a good and friendly group. Looking forward to learning about you and sharing common interests.

I live in the southwestern corner of Vermont, on 15 acres that are my little piece of paradise on earth! Passionate about photography, always improving my skills both with the camera and with LR and PS.

The best way IMHO to decide between cameras is to look at their specifications. That way you can see which features are different, or present/not present in each model. Then, depending on your budget and what suits your needs, you can rule in / rule out different models.

Go to the Nikon website and download the manuals for each camera. Near the end of each manual you will find the specifications. Other sites will let you do side-by-side comparisons, which is good. However, the presentation does not include as much as the camera manual. I discovered this when doing my own research and still had questions about some features. The camera manuals specifications list answered those questions!

Buy the best you can afford. As for lens and camera match-ups, it really is not that important. I use FX lenses on a DX camera with excellent results. Just lose some angle of view. And if you go for an FX camera, you can also use the DX lenses on it. But your current camera can be used as a backup instead of switching lenses when out taking photos.