Depth of Field

There are generally four image categories that are used in the field of dental photography today: macro intraoral, macro extraoral, portrait, and benchtop. Each type of photograph has an identifiable use and a calculated purpose when used to achieve specific imaginative goals. To this end, various lenses (Figure 1) and camera equipment are available to assist in the process. However, the interpretive style and emotive essence in each image type remains largely subjective and is based on the creative heart, mind, and vision of the photographer.

When considering dental photography, macro intraoral images are the most common type that are used for shade analysis (Figure 2) and shown in peer-reviewed journals, such as before-and-after-treatment photos (Figure 3). As the name suggests, these photographs are captured with a dedicated macro lens. By definition, macro photography is limited to lenses capable of producing images on the camera sensor that are at a magnification ratio that is at least equivalent in size to the subject being photographed. This is represented by a 1:1 designation on the barrel of the lens (Figure 4). The ability of the lens to faithfully reproduce objects on the sensor at true life size, or a 1:1 magnification ratio, is important because it allows the lens to focus at very close distances to the subject (eg, the patient's teeth) and helps to eliminate distortion of the final image.

The minimal focus distance of a standard lens, or "kit lens," does not allow for such up close photography or detail resolution without the aid of additional equipment, such as extension tubes (Figure 5). For the various reasons described here, a macro lens should be in the camera bag of every dentist and laboratory technician. It should be noted, that as an additional benefit, a 100-mm macro lens also doubles as an excellent piece of equipment for portrait photography. And for the financially conscious consumer, it is not necessary to purchase the red-line professional series or luxury "L" lenses (Figure 6) in order to acquire amazingly sharp and beautiful photographs.

If intraoral photography is the pumping heart of communication between the dental laboratory and the dentist, then extraoral photography is the life blood of communication between the dentist and the patient. These images extend beyond the borders of the mucosa and show the lips and skin tone of the patient. In doing so, they place the final restorative results in context and offer less graphic and consumer friendly content (Figure 7 and Figure 8). The texture and matte-finish character of the human epidermis responds differently to light than the glossy and moisture laden oral environment. Simple paper diffusers, placed over the flash heads attached to the camera, produce a more flattering, less institutional-looking photograph (Figure 9 and Figure 10). When documenting a case, note that the use of plastic and metal intraoral retractors can create red stretch marks and circumferential creases around the patient's mouth, so be sure to acquire all of the necessary extraoral images first.

Although not technically challenging to produce, portraits are perhaps the most difficult images to obtain throughout each phase of treatment. After all, dentists do have a notorious public relations problem. They hurt people, and they're expensive—what is there to grin about? Without the ability to establish trust and rapport with another individual, there is no level of sophistication or technical mastery with a camera that will provoke laughter or a true Duchenne smile from a patient (Figure 11). The power of portrait photography lies in the ability of these images to add a uniquely human element to an otherwise sterile and overtly clinical documentation process. A final cropped and edited headshot of a patient creates a fortuitous branding opportunity since these images will likely be the highest quality and most flattering photographs they possess (Figure 12, composite portraits). Not surprisingly, the patients often use these photos as profile pictures and post to social media. This is phenomenal, organic word-of-mouth marketing that was borne from your routine photography protocol.

The world of dentistry practically begs to be photographed. Aside from all of the essential patient-centered images, there is an infinite amount of material within the dental laboratory and throughout the operatories that provide captivating subject matter to satiate the artistic appetite of the camera (Figure 13 and Figure 14). Repeating shapes and the use of reflective surfaces, such as a mirror, offer exceptionally compelling imagery and force the viewer to observe the mundane details of the clinic in an entirely unique perspective (Figure 15 and Figure 16).

For the truly intrepid photographer, there is no glass that is more unforgiving or intimidating than Canon's MP-E 65-mm 1-5x macro lens (Figure 17). With the ability to reproduce images at five times life size, the addition of this lens into the mix allows for unparalleled intimacy with the subject (Figure 18 through Figure 20). The MP-E 65-mm lens has no ability to autofocus and trying to zero in on your subject has the parallax feel of a high-power rifle scope—the slightest movement or breath will completely alter the composition within the frame and throw the subject out focus. Due to the extreme minimum focusing distance, this lens possesses a very shallow depth of field which results in a heavily blurred background. A tripod is highly recommended accessory to this particular lens. In the same way that extraoral photography adds perspective to patient care, a wide-angle lens is well-suited at the bench to help establish a situational framework for the manufacture and fabrication of the prosthesis (Figure 21 and Figure 22).

There are myriad photographic techniques and technologies currently available to the dentist and laboratory technician. The manner in which these implements are utilized by the dental professional is largely dependent on the personal style and desired outcome of the individual. As a standalone resource, each type of photograph described is an essential component in the documentation protocol. When these singular images are combined, they merge into a meaningful and emotional storyline (such as Figure 23 through Figure 30), which ultimately improves communication and collaboration and aids in continued self-improvement. Most importantly, though, when the pictures reveal the nuance and details that the camera lens exposes about this remarkable profession, it's easier to understand there is so much more to the practice of dentistry than what normally meets the eye.

M. Reed Cone, DMD, MS, CDT
Nuance Dental Specialists
Portland, Maine