I have a Nikon D40X camera. Which lens is best to capture small insects, flowers or jewelry?

Ideally, you want a dedicated macro, but you could use a zoom like the 18-200. The thing is though that with a heavier lens, you are more prone to camera shake, so make sure you use a tripod whenever possible. Also, zooms have a depth of field issue. As the lens goes out further, the lens gets slower - i.e., the aperture setting gets higher. This will effect your depth of field which is important in macro photography and why a dedicated macro is better.

From Wiki:

There are different categories of macro lenses, depending on the focal length:

* 50–60mm range typically used for product photography and small objects
* 90–105mm range the standard focal range used for insects, flowers, small objects
* 150–200mm range gives more working distance — typically used for insects and other small animals
* a few zooms provide a macro option, but they generally do not allow a 1:1 magnification


Here's the rule of thumb ... the higher the aperture (f stop) the slower the lens. More from this article form How Stuff Works will help as well.