TriPod Boom
 

How does one take a photo from directly above...like taking a picture of a necklace laying flat on a surface? Do I need to purchase an "arm" for my tripod? Does anyone do this??

If you need to shoot straight down and need a tripod to hold the camera steady because you are shooting with longer exposures, then yes, a boom on your tripod does help a lot. I have a couple of different lengths for my tripod. Your tripod needs to be able to take one though and able to still be steady when the arm is out with the camera on it. Leg weights or sand bags or water bottles in a bag are handy to add weight to the legs to make it steadier.

If you are shooting at 1/60th or faster (or 1/30th if you can brace and have a normal steady hand) you can also just put the jewelry on the floor and shoot down that way. I also bought one of the 3 step kitchen step ladders that have wide steps and is solid feeling that I can stand on and shoot down onto a platform. Home Depot sales a square sawhorse type table that folds flat but opens up into a rectangle that is very handy, I've bought 3 of them. The top is about 17.5" x 19.5" square. I can't set my light tent on it directly but I have a 1/2" thick piece of plywood that is about 4'x4' that I set on top of it and set the tent on top of it. It's also handy when I need extra room for things, like my kiln shelf while I set glass up on it. I wish it adjusted up and down but that's minor.

Mike