Cosmetic dentistry beauty & science

I 23 special _ digital photography I cosmeticdentistry 3_2013 Fig. 7_If an exposure compensation setting of –1 is necessary for Nikon bodies, this may be different for Canon bodies and other camera/flash set-ups. particular requires attention. It is ensuring an adequate depth of field, which leaves little latitude but to select a small aperture opening, usually f/22 for all dental views.5 Use f/8 for portraits.2 The ISO setting controls the sensitivity of the camera’s capture chip or sensor to light. The lower the ISO number (e.g. 100 or 200), the less sensitivethechip,thesharpertheimage,andthe more light needed to obtain a good image. Con- versely, a higher ISO setting requires less light, but the image obtained can be noisy or grainy; in other words, less sharp. For dental photography, the recommended ISO setting is 200. Automatic ISO setting is not recommended for dental photography.2 You may find that you need to experiment a bit to obtain just the right amount of light for correct exposure by changing exposure com- pensation.6 Flash-to-subject distance influences light in- tensity, which depends on the inverse-square law. Simply stated, illumination is less bright the further away from its source because it has a greater area to cover. The inverse-square law is applicable when taking intra-oral images using mirrors. In these circumstances, the light from the flashes travels a greater distance by being reflected off the mirror surface before it can illuminate the teeth. Exposure compensation is therefore necessary (e.g. –0.7) to avoid under-exposed images.6 Exposure compensation is also necessary (e.g. –1.3) to avoid over-exposed close-up re- tracted views. However, exposure compensation should be set once for all views. You may find that you need to experiment a bit to obtain just the right amount of light for correct exposure by changing exposure com- pensation.7 If an exposure compensation setting of –1 is necessary on dental views for Nikon bodies (Fig. 7), this may be different for Canon (please note that a shutter speed set to 1/200 in manual mode is necessary for Canon bodies, while for Nikon bodies the shutter speed is set automatically) and other camera/flash set-ups. _Conclusion For dental photography, it is essential to have a small aperture opening, f/22 for example, so that as many teeth as possible or a large area of soft tissue is in focus. In theory, to obtain a greater depth of field one could consider using an even smaller aperture, f/32 for example, but this deteriorates the image quality owing to diffraction. Therefore, setting the aperture to smaller than f/22 will diminish image clarity considerably without a substantial gain in depth of field.5 Optimum settings for dental photography: _(1:15), f/8 for portrait photography; _(1:3), f/22 for dental views, including normal smile and retracted views, as well as occlusal views; _(1:1.5), f/22 for dental views, including close- up retracted views. Thisarticlehasofferedasimplesettingsguide based on the author’s experience on capturing the standard photographic views required in aesthetic dentistry.8_ Editorial note: A list of references is available from the author. TheauthorwantstothanktheESCD(www.escdonline.eu) anditsmembersfortheirfriendshipandsupport. Dr François Grossetti 10,avenue de l’Opéra 75001 Paris,France docteur.grossetti@ dentiste-cosmetique.com www.dentiste-cosmetique.com cosmeticdentistry_author Fig. 7