The best way I’ve found for taking photos of jewelry is to make
a “light tunnel” out of tracing or layout paper. A tube of
about 8-10 inches in diameter and 20 inches or so long.
Place this on a desk or tabletop near a window with a good
amount of light coming in. I would keep the light from
striking the paper tube directly. Cover the far end of the tube
with another piece of layout/tracing paper by draping a scrap
Place your jewelry inside the tube (6 or 8 inches) Place your
automatic 35mm camera on a beanbag with the lens inside the
tube, focus, shoot. No flash. I guarantee this will be the best
jewelry picture you will ever have taken so easily.
The paper diffuses all the light; the shadows and reflections
are brought to a minimum. You can even experiment in the
evening with no sunlight, remove the flash from the camera(but
leave the din cord plugged in). Open the shutter and flash
multiple times at the paper tube from different angles, close
the shutter. Since this method eliminates the automatic
exposure, some experimentation is necessary to get the correct
flash/exposure ratio. 100asa will be around 3 or four flashes
held about 10" from the tube with a “small” flash unit.