File formats

Today, the majority of “prosumer” (professional consumer) and professional digital single-lens reflex (DSLR) cameras have the ability to record captured images in a type of file known as “raw”—though the actual file extensions and compatibility of these is not completely standardized or universal. The raw format essentially holds on to all of the recorded data at the time of capture without making postprocessing decisions that irreversibly alter the interpretation of this data. This information can be adjusted after it is uploaded to computer, maintaining the flexibility to always go back to the original, unaltered image file. Analogous to the latent image recorded on film, the image data must be processed to create a useable photograph. The Joint Photographic Experts Group (JPEG) format is perhaps the most widely used file format for general sharing of digital photos and is used by point-and-shoot cameras; JPEG images are actually a compressed form of the original data that a camera sensor is capable of capturing. This compression trades some data for more manageable file sizes. When elements of a photograph are critical to keep accurate and repeat editing is a concern (saving a JPEG repeatedly will compound data compression and enhance noise), the photographer should shoot in the raw format.

There is no single raw format, however. Different camera manufacturers—namely, Nikon and Canon—develop their own file language that requires their own code to decipher them. Raw editing software is capable of handling more than one type of raw file, but it must be updated with multiple file types (there are over 100 different raw formats). The proprietary nature of these formats is a subject of concern for some photographers, raising the question of the lifespan of digital photographs over that of physical film. Since raw files are proprietary by nature, much of the data interpretation and usability is controlled by the manufacturers and software developers. If a format ceases to be supported by the software, the user is left with files that cannot be opened.

In an effort to address this concern, Adobe Systems Incorporated introduced a new type of raw file in 2004: the Digital Negative (DNG), with the goal of establishing a “legacy” format that will remain compatible for years to come and to establish a future-proof solution for archiving digital photographic files. As Adobe’s press release of the time stated, “current raw formats are unsuitable for archiving because they are generally undocumented and tied to specific camera models, introducing the risk that the format will not be supported over time.” The format is naturally supported by Adobe’s own product line (Bridge, Photoshop, Photoshop Elements, Lightroom), but is also supported by GIMP, Corel Paint Shop Pro X, and Apple’s Aperture 3. The debate continues on whether the DNG format is a suitable legacy format.

If long-term storage and organization of dental photographic files is an important element to the photographer’s workflow and archiving needs, the DNG format is worth exploring in depth. A small number of cameras are able to output directly to DNG, including some Leica, Samsung, and Hasselblad models; any common raw format such at NEF (Nikon) or CR2 (Canon) can be converted after the fact using software such as Adobe Camera raw or Adobe’s DNG Converter. The DNG files retain raw functionality and in some cases can prove to be more compatible with other software.

Digital cameras and equipment

Digital cameras are constantly evolving with more megapixels, better low-light performance, and dozens of other features to stand out among the numerous options available to the professional and the consumer alike. One issue that has plagued DSLR cameras is dust accumulating on the Charge-Coupled Device (CCD) sensor. This occurs because of the interchangeable-lens capability of the DSLR, something that a photographer will make use of when switching between a “normal” lens (18 mm–50 mm) to a macro lens for close-up work. As a point of reference, in 2005, one of the only cameras designed to address this issue in its hardware was the Olympus E-1. This camera featured a vibrating sensor that knocked any resting dust particles off the CCD. Since then, many camera models have adopted similar technologies. The Canon 5D Mark II, for example, uses ultrasonic vibrations each time the camera is turned on and off to ensure that new dust particles do not hinder photographs taken after switching lenses. This camera also features a 21.1 megapixel sensor, which may be more pixel resolution than is necessary for screen display or small prints. This is a key aspect to consider when upgrading camera bodies; the upgrade should be justified in terms of other factors and not simply megapixels because this alone does not offer a benefit to workflow or output potential in the context of a dental practice, especially when considering the additional storage space needed to the accommodate larger files sizes that a larger sensor produces.

For general dental photography, the combination of a macro lens and ring flash is a highly capable imaging system. The Canon MR-14EX Macro Ring Lite is Canon’s own flash unit that has been around for a number of years, while Nikon users have the R1 Wireless Close-Up Speedlight System. Though they have somewhat different form factors, they have the flexibility of controlling lighting ratios and firing one or both sides for more directional or even light, respectively. A second option for Nikon cameras is the Canfield Twinflash, a third-party flash unit that has the option of attaching a flip-down set of polarizing filters to eliminate reflections from wet surfaces.

For the advanced user with a strong grasp on raw processing, including a calibrated reference such as a color checker in photographs for postprocessing color accuracy is a great idea. Many portable products have emerged recently for the “on-the-go” photographer that double as useful macro photography color checkers. These products include the X-Rite ColorChecker Passport and the Macbeth ColorChecker Mini. By including these small cards in dental photographs, the “eyedropper” or comparable tool in Photoshop, Lightroom, or other similar software can establish an accurate white point. This means that sensitive colors such as the shades of teeth can be consistently processed over multiple images and thus over time.

Digital cameras and equipment

Digital cameras are constantly evolving with more megapixels, better low-light performance, and dozens of other features to stand out among the numerous options available to the professional and the consumer alike. One issue that has plagued DSLR cameras is dust accumulating on the Charge-Coupled Device (CCD) sensor. This occurs because of the interchangeable-lens capability of the DSLR, something that a photographer will make use of when switching between a “normal” lens (18 mm–50 mm) to a macro lens for close-up work. As a point of reference, in 2005, one of the only cameras designed to address this issue in its hardware was the Olympus E-1. This camera featured a vibrating sensor that knocked any resting dust particles off the CCD. Since then, many camera models have adopted similar technologies. The Canon 5D Mark II, for example, uses ultrasonic vibrations each time the camera is turned on and off to ensure that new dust particles do not hinder photographs taken after switching lenses. This camera also features a 21.1 megapixel sensor, which may be more pixel resolution than is necessary for screen display or small prints. This is a key aspect to consider when upgrading camera bodies; the upgrade should be justified in terms of other factors and not simply megapixels because this alone does not offer a benefit to workflow or output potential in the context of a dental practice, especially when considering the additional storage space needed to the accommodate larger files sizes that a larger sensor produces.

For general dental photography, the combination of a macro lens and ring flash is a highly capable imaging system. The Canon MR-14EX Macro Ring Lite is Canon’s own flash unit that has been around for a number of years, while Nikon users have the R1 Wireless Close-Up Speedlight System. Though they have somewhat different form factors, they have the flexibility of controlling lighting ratios and firing one or both sides for more directional or even light, respectively. A second option for Nikon cameras is the Canfield Twinflash, a third-party flash unit that has the option of attaching a flip-down set of polarizing filters to eliminate reflections from wet surfaces.

For the advanced user with a strong grasp on raw processing, including a calibrated reference such as a color checker in photographs for postprocessing color accuracy is a great idea. Many portable products have emerged recently for the “on-the-go” photographer that double as useful macro photography color checkers. These products include the X-Rite ColorChecker Passport and the Macbeth ColorChecker Mini. By including these small cards in dental photographs, the “eyedropper” or comparable tool in Photoshop, Lightroom, or other similar software can establish an accurate white point. This means that sensitive colors such as the shades of teeth can be consistently processed over multiple images and thus over time.