LMT has provided an opportunity for us to help one another grow by sharing our knowledge via blogging. Since dental photography is such a valuable aid to us as technicians with regard to self-assessment, learning, communication and marketing; I thought I'd share what I've learned with you. Although it can be a little overwhelming in the beginning, the most important thing to know is you don't have to be a professional or even know a lot about your camera to get some really good consistent results with only an elementary understanding and some basic bits of knowledge.
A macro lens is not mandatory for every aspect of dental photography but if you want one the recommended standard minimum is a 100mm. You will want one for in the mouth documentation.
The recommended flash is a dual flash but I've learned with a few tricks the standard ring flash yields excellent results. When I use my ring flash it is always detached from the camera body and held high above the object. You can play with varying levels of height and angle. Depending on the desired effect, I'll sometimes place it lower and off to the side - as in this photo: http://www.lmtmag.com/photos/2972 and also in this one: http://www.lmtmag.com/photos/2696 . Here I placed the ring flash directly on the mat, off to the left, light facing down. This created a lateral dispersion of light and because natural teeth allow light to refract and pass through, it created a cool effect.
The time of day effects the amount of light as does the background. I use a black, matte finish desk mat from staples. Sometimes I use my piano finish speakers if I want to create a reflection. Be creative! You can even make a cut out of regular ink jet paper and create a filter over the flash. A light box is not necessary to get excellent results but you can use that too. When photographing in the mouth you should use a black background. A black background allows the sensor to determine the black and white point on RGB color space which is crucial in determining the value of a shade. (you can read more about that concept in "Photography in Dentistry" by Pasquale Loiacono and Luca Pascoletti.)
Manual settings yield the best results. This was the most intimidating part for me till I learned that in dental photography we want to restrict ourselves to these settings:
Six anteriors: 1. F/stop = F/22-F/32 2. Shutter speed = set at 1/100
3. ISO setting at 100 or 200
Two Central Incisors: The F/stop can be opened much lower since the object is "narrow' and the plane of the teeth is practically parallel to the sensor plane, and the distance doesn't change as it does when the corner is turned at the canines.
Posterior teeth (distal of canines) : F/stop =32 since the distance is longer from the object to the focal plane of the sensor.
Well, looks like I'm out of space. I hope you find this information useful and I hope you'll have something to teach me as well. It's such fun. Enjoy!