The need for a good lens is first and up with that is practice with
lighting. Getting good macro shots of a dragonfly, a rose, a chess
piece…well, those are not difficult with experience. As for
jewelry, those who have not tried it in macro photos may be very
surprised at the initial difficulty compared to other macro subjects
they may have mastered! It all has to do with radiance of the stones
and reflections of metals. As I mentioned previoiusly, sometimes
controlled glare or reflection is a plus. This depends on whether you
want a technical shot or something more akin to an advertising photo.
Practice and do experiment with lighting. Tripod and manual focus are
a must. (With enough light, you can skip the tripod but if you want
to overlay photos, tripod is totally needed.) Practice with objects
to control reflections such as first, diffusing light on metal. Then,
practice with things in the area such as papers rolled up or hanging
to control the color of reflections.
If shooting a gemstone only, that will need the point sources of
light. Anunmounted opal may be very well shot while immersed under
water with manual focus and no debris on the water surface to give
it away! Go for it.
I mentioned a Sigma lens, 50mm as one I use. I also have a 105mm
Sigma macro which is 1:1. The longer lens has less use outside macro
but in macro use does give more working room. These lenses do well.
Do not skimp on the lens. It does not have to be the best from Nikon
since some others do as well. Beware of cheap lenses in this
You will find the focus depth of field is quite limited, meaning
only some portion of the item may be in focus depending on the item,
lens and aperture setting. Experiment with where the focus is sharp,
on a prong, on the stone table or deeper into the jewelry. See the
effect of depth of field which can enhance the photo or ruin it to
Best wishes overall. Tom.