Jack’s answer on microscopes was excellent.
For photography, believe or not, I use a flat bed scanner. You need one that has some 3d capability (the one on my printer can only scan paper thin items as with all paper feed scanners). Currently I am using an older Epson V300 but a V600 would probably work. By adjusting the dpi setting you can magnify to an incredible amount. The attached image is a 6mm cookie cutter tooth (Isistius) at 1200 dpi and a 6-gill (Hexanchus) tooth scanned at 600 dpi. At 9600 dpi you could paper your wall with it. You have to do some post processing such as cleaning up dust, removing background reflections and adjusting brightness and contrast but you have to do that with a camera as well. The problem with a camera is that setup takes forever and then you have to readjust almost after each picture and play with the lighting, the lens and the settings. A scanner takes far less time and I believe produces superior images. Larger items can be scanned as well. Attached is a scan of an almost 7 inch megalodon and a quarter of a nurse shark (Ginglymostoma) jaw. Here is a link to a how-to guide: http://www.elasmo.com/frameMe.html?file=refs/terms/scanning.html&menu=bin/menu_refs-alt.html