Yesterday I was able to take a tour of the GIA facility in Carlsbad, CA. The GIA are the people who train jewelers to know which stone, is what gem, and how to consistently grade stones.
The lighting is very challenging because of the thick protective glass that you have to shoot through, and high intensity lighting in dark rooms.
Generally I have my auto ISO set with a maximum of 3200, but because of the conditions I increased the maximum to 6400.
I was surprised at the detail in this shot @ISO 6400
Here is an one taken at ISO 250
Comments are welcome